LR247.2.1: Rock Cycle

What do all of these pictures have in common? They all show different kinds of rocks! There are many kinds of rocks found on Earth's surface. Rocks come in many different shapes, sizes, and colors. All rocks are solids that are made up of one or more minerals. Even though there are thousands of minerals on Earth, only a few dozen are found in rocks.

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All rocks are made up of__________.

Scientists can identify different rocks by looking at the minerals inside them. There are many different kinds of rocks made up of different mineral combinations, and each kind of rock is formed in a different way. Scientists classify rocks into three main groups:
• igneous
• sedimentary
• metamorphic

Granite is an igneous rock.

Sandstone is a sedimentary rock.

Marble is a metamorphic rock.

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Which is NOT one of the three kinds of rocks?

Igneous rocks form when molten rock, called magma or lava, cools down and hardens. Crystals often form in the igneous rock when the magma or lava cools down.

As this lava cools, it becomes igneous rock.

Some igneous rocks form when magma cools and hardens below the surface of the Earth. This process can take a long time. The long amount time allows large crystals to grow in these igneous rocks.

Granite is an igneous rock that forms underground. Each of the different colors in the rock are crystals.

Lava cools and hardens quickly on the surface of the Earth. The igneous rocks that form from lava tend to have tiny crystals; some have crystals so small they can only be seen with a microscope.

Obsidian is an igneous rock that forms above ground. The crystals in obsidian are not visible because they are so small.

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While she is on vacation with her family, Allyson finds many igneous rocks. Which of these locations probably contains the most igneous rocks?

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Sierra finds an igneous rock with very large crystals in her backyard. Was the rock most likely formed underground or above ground?

Sedimentary rocks form differently. As rocks are slowly worn away by rain, sun, wind, and water, little bits of the rock are carried away and deposited in other places. These tiny pieces of rock are called sediment. When layers of sediment settle on top of each other and harden, they become sedimentary rocks. Some sedimentary rocks contain big pieces of sediment. Others contain tiny grains of sand.

The different colors in this sedimentary rock are caused by different particles in the sediment.

Some sedimentary rocks also contain fossils. Millions of years ago, some animals died in riverbeds. Their bodies were covered with sediment from the river. Their soft organs rotted away, but their bones turned into rocks. They can now be found as fossils in sedimentary rocks.

This ancient fish was buried under sediment millions of years ago. Now it is a fossil.

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As rocks are slowly__________, little bits of rock called__________
are carried away and deposited in other places. When these layers harden, they are called__________.

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Lily says that sedimentary rocks form over a short period of time. Is she correct?

Metamorphic rocks form when igneous, sedimentary, or even other metamorphic rocks are changed by extreme heat and pressure. The incredible heat and pressure causes the old rock to change into a new rock with new properties. New minerals can be formed through this process.

This rock is marble. It was once the sedimentary rock limestone. After experiencing intense pressure and heat for thousands of years, the limestone was changed into marble. This is one example of how metamorphic rocks are made.

Heat alone is not enough to change a rock into a metamorphic rock. The heat must be accompanied by powerful pressure to cause the changes to the old rock necessary to create a metamorphic rock. Two places where metamorphic rocks are often found are deep within mountains or just underneath the ocean floor. Both these places experience very high pressure and exposure to hot temperatures.

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What two things need to be in the environment in order for metamorphic rock to form?

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Click on the boxes that are facts about metamorphic rocks. (choose 2)

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This rock has large crystals in it. It was formed when molten magma cooled down and hardened. What kind of rock is it?

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Drag the correct kind of rock to each definition below.

Sandra is digging a foundation for a shed in her yard when she finds an interesting looking rock. Which of the following most likely describes the age of the rock she finds?

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What is a rock?

Check for Understanding:

There are three main kinds of rocks: igneous, sedimentary, and metamorphic.

The rock cycle is the process that makes one kind of rock change into another kind. The rock cycle is constantly forming and destroying rocks.

Rocks make layers as they form. The layers closest to Earth's surface are the youngest. The deepest layers are the oldest.

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Click on the igneous rock.

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Click on the metamorphic rock.

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What do all rocks contain?

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Where are igneous rocks formed?

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Which type of rock is formed when other solid rocks are heated and put under pressure?

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Giancarlo is looking at a rocky cliff face. He notices:

•The cliff is made of a rough-feeling rock that has stripes of different colors.
•Some of the stripes are wide, and some are narrow.
•The stripes mostly run in straight lines from left to right.
•The stripes run for the entire length of the cliff wall.

Which kind of rock is the cliff most likely made of?

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How often are rocks changing?

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LR247.2.1: Rock Cycle

Which is NOT one of the three kinds of rocks?

While she is on vacation with her family, Allyson finds many igneous rocks. Which of these locations probably contains the most igneous rocks?

Sierra finds an igneous rock with very large crystals in her backyard. Was the rock most likely formed underground or above ground?

Lily says that sedimentary rocks form over a short period of time. Is she correct?

What two things need to be in the environment in order for metamorphic rock to form?

Click on the boxes that are facts about metamorphic rocks. (choose 2)

This rock has large crystals in it. It was formed when molten magma cooled down and hardened. What kind of rock is it?

Sandra is digging a foundation for a shed in her yard when she finds an interesting looking rock. Which of the following most likely describes the age of the rock she finds?

What is a rock?

Click on the igneous rock.

Click on the metamorphic rock.

What do all rocks contain?

Where are igneous rocks formed?

Which type of rock is formed when other solid rocks are heated and put under pressure?

How often are rocks changing?

What does the rock cycle describe?

Which is NOT one of the three kinds of rocks?

While she is on vacation with her family, Allyson finds many igneous rocks. Which of these locations probably contains the most igneous rocks?

Sierra finds an igneous rock with very large crystals in her backyard. Was the rock most likely formed underground or above ground?

Lily says that sedimentary rocks form over a short period of time. Is she correct?

What two things need to be in the environment in order for metamorphic rock to form?

Click on the boxes that are facts about metamorphic rocks. (choose 2)

This rock has large crystals in it. It was formed when molten magma cooled down and hardened. What kind of rock is it?

Sandra is digging a foundation for a shed in her yard when she finds an interesting looking rock. Which of the following most likely describes the age of the rock she finds?

What is a rock?

Click on the igneous rock.

Click on the metamorphic rock.

What do all rocks contain?

Where are igneous rocks formed?

Which type of rock is formed when other solid rocks are heated and put under pressure?

How often are rocks changing?

What does the rock cycle describe?