LET’S ROCK!The Rock Cycle

ROCKS Rocks are mixtures of minerals. There are 3 main types of rocks. Scientists classify rocks according to

how they are formed.

TYPES OF ROCKS Igneous Rocks are formed from cooled

magma or lava. They usually have large or small

crystals that you can see. Some igneous rocks have holes made

by gas bubbles.

TYPES OF ROCKS Sedimentary Rocks are formed when

bits of rock, shells, and the remains of plants and animals are pressed and cemented together.

These usually have flat layers you can see.

Some contain fossils. They are usually softer than igneous or

metamorphic rocks.

TYPES OF ROCKS Metamorphic Rocks are formed from

existing rocks that have been squeezed and heated deep inside Earth’s crust.

Some have layers that look like dark and light bands.

They will break along the bands.

KEY TO ROCK IDENTIFICATION

*Not all rocks can be indentified using this key

THE ROCK CYCLE Rocks can change into other kinds of

rocks. We call this process the rock cycle.

There are 5 stages in the rock cycle. Melting Cooling and Hardening Weathering and Erosion Squeezing and Cementing Squeezing and Heating

MELTING Deep below Earth’s surface, all three kinds

of rock are melted to form magma.

Rock Cycle Diagram

COOLING AND HARDENING On or below Earth’s surface, magma

cools and hardens to form igneous rock.

Rock Cycle Diagram

WEATHERING AND EROSION Weathering breaks existing rock into tiny

particles, forming sediment. Erosion moves the sediment to other places, where it is deposited.

Rock Cycle Diagram

SQUEEZING AND CEMENTING The sediment is squeezed together and

cemented to form sedimentary rock.

Rock Cycle Diagram

SQUEEZING AND HEATING Heat and pressure change sedimentary

rock and igneous rock into metamorphic rock.

Rock Cycle Diagram

Watch the Rock Cycle Study Jam