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6th Grade Science / Lesson 6 - Metamorphic Rocks

Metamorphic Rocks
What will we be learning today?

  • In this lesson, we are going to learn about Metamorphic Rocks.

  • We will begin today's lesson, by defining Metamorphic Rocks.

  • Metamorphic rock is when igneous and sedimentary rocks can be changed into a different kind rock by extreme heat or pressure, or both, within the earth.

  • The Process of Metamorphic Rocks

    • In the process the original rock does not melt under heat and pressure. If it did, it would become an igneous rock.

    • The rock becomes different from the original rock

    The Process of Metamorphic Rocks

    • The original rock remains solid but

    • 1) Mineral grains in the original rock may flatten and line up

    • 2) Minerals may change their identity

    • 3) Minerals in the original rock may separate into layers of different densities

    Metamorphic Rocks Are Useful

    • Slate is used for roofing shingles as well as stepping stones and outdoor floors.

    • Marble is used for making statues, floors, countertops and monuments.

    • One kind of coal is a metamorphic rock, called anthracite, or hard coal. Anthracite is formed from soft coal.

    • Rocks are continually changing from one to another in never-ending cycle called rock cycle

    • The rock cycle has no beginning and no end

    • Lava cools and hardens into igneous rock

    • Weathering breaks down the rock into pieces. The pieces are washed into an ocean. Over time layers build up and harden into sedimentary rock.

    • Then it gets crumpled and pushed underground and it changes to metamorphic rock.

    • Metamorphic rock is pushed down and starts to melt. Where the whole rock cycle starts all over again.

    Let's Review What We Learned Today!

    • Metamorphic Rocks : when heat and pressure change rocks

    • Rock Cycle : never-ending process by which rocks are changed from one type into another