Rocks

How They Are Made

By

Mr. Haynes

Volcanoes

• Volcanoes are made of many things that make rocks.

• The three parts of a volcano are magma, lava, and the crust.

Magma is molten rock below ground.

 

 

Magma is extremely hot! Great pressure from under ground pushes the magma to a crack in the crust of the earth. Then a volcano forms.

The volcano erupts.

• Lava is molten rock above ground.

• Lava shoots out of the volcano and runs down the crust.

• The crust is the side of the volcano.

Lava is extremely hot!

When the lava cools, it turns into different forms of rocks.

There are three forms of rock. They are igneous, sedimentary, and metamorphic.

Igneous rock forms when magma cools above or below ground.

• Granite is an igneous rock with shiny speckles. It is a very heavy rock.

Sedimentary rock is formed when tiny bits of rock are pressed together underwater.

• Most fossils are found in sedimentary rocks.

• Sedimentary rock is made over millions of years at the bottom of lakes and rivers.

• Sandstone is a sedimentary rock.

Metamorphic rocks are rocks that have been changed by

heat, pressure, and millions of years. • Metamorphic rocks were

once sedimentary or igneous rocks.

• Quartz is a metamorphic rock.

3 Types of Rocks

• Igneous- formed when magma cools

• Sedimentary- formed when tiny bits of rock are pressed together

• Metamorphic- formed when rocks are changed by heat, pressure, and time

CSUN