Our edible metamorphic rock activity is a fun way to learn about how metamorphic rocks form. Metamorphic rocks are one of three types of rocks along with sedimentary rocks and igneous rocks.

Edible science experiment to make Slow Cooker Walnut and Cranberry Fudge as an example of Metamorphic Rocks

Learning about Metamorphic Rocks

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Metamorphic rocks form when existing rocks (either sedimentary, igneous, or metamorphic) are exposed to high heat, high pressure, and/or hot mineral-rich fluids. It’s this heat and pressure that push and squish and change the rock into a new type of rock. There are different types of metamorphic rocks based on what type of rock it started as. Have you ever heard of marble? It’s just one type of metamorphic rock. Purchase a set of metamorphic rocks like the one below to help study the different types. Metamorphic rocks are difficult to find just out and about since they usually form deep within the earth’s crust or near tectonic plate boundaries (where lots of heat and pressure exist).

Learn more about Rocks and Fossils with our Activities for Earth Science.

Edible Metamorphic Rock Activity – Make Slow Cooker Cranberry Walnut Fudge

This simple slower cooker fudge recipe is an easy way to show how metamorphic rocks form. We start with chocolate chips and pieces of chocolate. This represents sedimentary rock layers. Adding cranberries and walnuts represents the fossils that were once part of a sedimentary rock. Sometimes fossils can be found in metamorphic rock but often they are squashed and unrecognizable – kind of like when we cut into the fudge.

The heat from the slow cooker and stirring represent the heat and pressure changes that occur to make metamorphic rock. Our end product – the fudge – doesn’t look like the beginning chocolate pieces.

Ingredients for the Edible Metamorphic Rocks Cranberry Walnut Fudge

This is a version of our original slow cooker fudge recipe.

Try these Layers of the Earth Sugar Cookies for more Edible Science Models that you can make with kids.

Instructions for Making Slow Cooker Cranberry Walnut Fudge

Add the chocolate, butter, vanilla extract, and sweetened condensed milk to your slow cooker.

Edible science experiment to make Slow Cooker Walnut and Cranberry Fudge as an example of Metamorphic Rocks

Add in the cranberries and walnuts.

Edible science experiment to make Slow Cooker Walnut and Cranberry Fudge as an example of Metamorphic Rocks

Heat on low for 2 hours stirring every 15 minutes. Line a square baking dish with parchment paper. Pour melted fudge into the lined baking dish. Refrigerate until set. Cut in cubes. Store in a sealed container in the refrigerator.

Edible science experiment to make Slow Cooker Walnut and Cranberry Fudge as an example of Metamorphic Rocks

This is such an easy fudge recipe that kids can help add all of the ingredients to the slow cooker. It’s a bit difficult for them to stir, so that’s probably a job for an adult.

Cranberry and Walnut Slow Cooker Fudge Recipe

Slow Cooker Walnut and Cranberry Fudge Recipe

Edible science experiment to make Slow Cooker Walnut and Cranberry Fudge as an example of Metamorphic Rocks
5 from 1 vote
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Course: Dessert
Author: Cerys Parker

Ingredients

  • 500 g of chocolate chips or chocolate pieces milk chocolate, and white chocolate
  • 1 tablespoon unsalted butter
  • 1 teaspoon vanilla extract
  • 1 can sweetened condensed milk

Instructions

  • Add the chocolate, butter, vanilla extract, and sweetened condensed milk to your slow cooker.
  • Add in the cranberries and walnuts.
  • Heat on low for 2 hours stirring every 15 minutes. 
  • Line a square baking dish with parchment paper.
  •  Pour melted fudge into the lined baking dish. 
  • Refrigerate until set. 
  • Cut in cubes.
  •  Store in a sealed container in the refrigerator.
Tried this recipe?Mention @rainydaymum or tag #rainydaymum!

This is our favourite slow cooker – it’s large enough to contain LOTS of fudge and useful for batch cooking meals for the family as well.

So that your food doesn’t always have a lingering flavour of the last thing cooked we recommend using Slow Cooker Liners in all of your uses for the slow cooker. They will make it easier to clean too which is always a bonus.

I use a Square Cake pan when making fudge either a silicone 8inch pan or one with a removable bottom always lined with parchment paper to avoid the fudge sticking whilst it cools.

Recommended books to read and keep on rocks, fossils and Earth science for kids of all ages. With fiction and non-fiction recommendations but full of factual accounts plus hands-on activity books there are ideas to inspire and inform kids to want to learn more.

Looking for recommendations of Reading Material on Rocks then check out or Rocks, Fossils, and Earth Science Book Recommendations for Kids.

Learning about Rocks

Break Your Own Geodes

Geodes are a fantastic to explore with kids and this break your own Geode set from Steve Spangler Science makes it possible for kids to smash open some geodes themselves and discover the crystal lined inside.

Volcanoes


Let your child become a Volcanologist with a Green Kids Craft Volcano Science set – with 7 different science and creative activities included this would be great to use as part of a study on Earth Science and rocks.


Become a real geologist as you and your child test and learn about rocks and minerals with this hands-on learning science kits. Containing 30 different samples and full instructions you’ll soon learn what you need to do and can then use this skills on other rocks and minerals that you find.

 

Add to your Non-fiction book collection with these 3 favourite books to support learning, encourage investigation and extend your and their knowledge. The first is a field guide from the National Geographic Book Range on Rocks and Minerals, with this guide it aims to get kids out, exploring and discovering more about the rocks around them. The second – a Geology Lab for Kids has 52 different science activities and experiments for kids perfect for encouraging your child to get hands-on learning about Earth Science. The last is a reference book covering rocks and minerals which will help you answer all of the inevitable questions that kids and you may have as you turn your hand to learning and exploring about rock science and geology.

More Edible Rock Activities for Kids

Pin This Edible Science Activity to do Later

Edible science experiment to make Slow Cooker Walnut and Cranberry Fudge as an example of Metamorphic Rocks
Edible science experiment to make Slow Cooker Walnut and Cranberry Fudge as an example of Metamorphic Rocks
Author
Trisha Stanley

Trisha is an educator with a passion for science literacy and mom to Aiden, Lily, and Elon.

She’s the creator of Inspiration Laboratories, a blog dedicated to encouraging learning through creativity and play.

4 Comments

  1. Dear Trish,
    These are fantastic ideas! I would love to make this metamorphic fudge with my class, unfortunately, any recipes must be nut-free. Do you have any other suggestions for fossils instead of the walnuts?
    Julie

    1. Hi Julie,

      With a class, I would probably switch the walnuts for a cookie/biscuit something that will remain solid. We used Malted Milk or Nice biscuits in the past. Hope that helps

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