Vocabulary Magma: hot molten rock under the Earth’s surface Lava: hot molten rock above the...

Igneous RocksIntrusive and Extrusive

Igneous rocks are VOLCANIC ROCKS

They are molten rock that cools either above or below the Earth’s surface.

Vocabulary

Magma: hot molten rock under the Earth’s surface

Lava: hot molten rock above the Earth’s surface

Mineral: Molecules arranged in a regular pattern that are the “ingredients” of rocks.

Intrusive Igneous Rocks

Intrusive rocks are formed when MAGMA cools underground.

It is called intrusive because it INTRUDES on other rock layers

Intrusive Igneous Rocks

Intrusive rocks cool SLOWLY because they are underground where it is hotter.

Because they cool slowly they have BIGGER crystals (crystals have more time to grow).

Extrusive Igneous Rocks

Extrusive Rocks are formed when LAVA cools above the Earth’s surface.

They are called extrusive because they EXplode

Extrusive Igneous Rocks

Extrusive rocks cool more QUICKLY because they are out in the open

Because they cool more quickly they have SMALLER crystals (crystals have less time to grow).

Let’s see it in action…

http://www.classzone.com/books/earth_science/terc/content/investigations/es0603/es0603page05.cfm?chapter_no=investigationhtt