Geology Rocks: Igneous Rocks

Contributor: Meghan Vestal. Lesson ID: 11099

Is it hot where you are? Can you melt rocks on the sidewalk? Igneous rocks are formed from melted matter in the Earth. There's no reason to be ignorant about igneous rocks when you try our experiment!


Earth Science

learning style
Kinesthetic, Visual
personality style
Lion, Beaver
Grade Level
Middle School (6-8)
Lesson Type
Dig Deeper

Lesson Plan - Get It!


What do rocks have to do with exploding volcanoes and hot lava? Let’s find out!

In this series, entitled Geology Rocks, you will learn about the different classifications and types of rocks. The Related Lessons can be found in the right-hand sidebar.

Rocks tell us about the past and are an important resource used in the construction of homes and businesses.

There are three classifications of rocks:

  • Igneous
  • Metamorphic
  • Sedimentary

In this lesson, you will learn about the characteristics and formation of igneous rocks.

Some say igneous rocks have the most exciting formation process because igneous rocks are formed from magma.

Magma is a hot, molten liquid that resides below the Earth’s surface. When magma appears outside the Earth, we call it lava. The inside of the Earth can reach temperatures up to 13,000 degrees Fahrenheit! The temperature is so hot that it causes rocks and other materials inside the Earth to melt. This melted liquid is magma.

Magma that cools inside the Earth is referred to as intrusive igneous rocks. Intrusive igneous rocks, such as granite, have large crystals. When lava cools and hardens above the Earth’s surface, it is referred to as extrusive igneous rocks. The crystals in extrusive igneous rocks are much smaller than the crystals in intrusive igneous rocks. When magma or lava cools it becomes igneous rock.

Igneous rocks make up the majority of the Earth’s crust. They are characterized as having crystals and being porous. Sometimes the pores in igneous rocks are large enough to appear as tiny bubbles in the stone.

Extrusive igneous rocks typically have a glassy surface. Examples of igneous rocks include granite, pumice, obsidian, and basalt. Have you seen or heard of any of these types of rocks before? Share what you know or have seen with a teacher or parent.

To learn more about how igneous rocks are formed, watch Click View AU/NZ’s Igneous Rocks ACSSU153 (below):

Watch the StudyJams! Igneous Rocks slideshow to see examples of igneous rocks. When you visit the StudyJams! site, just click the green Slide Show button. You will Test Yourself later in the lesson.

Look at the image and question in the beginning of this lesson. What do rocks have to do with exploding volcanoes and hot lava? Explain your answer to a teacher or parent.

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