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How are Rocks Formed?. Engagement. Observe the sample rocks and choose one and write a description. (using your five senses). Students will observe and classify characteristics of rocks and read text pp. 198-199 in order to create a “3 Tab” foldable. Objective:. Rocks.
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Engagement Observe the sample rocks and choose one and write a description. (using your five senses)
Students will observe and classify characteristics of rocks and read text pp. 198-199 in order to create a “3 Tab” foldable. Objective:
Rocks In this lesson you will learn about the rock cycle and what some kinds of rocks there are on Earth. First thing we will begin with is identifying the three main different kinds of rocks. Below are three different kinds of rocks. Using what you already know about rocks, can you determine what kind is which?
Group Work Classify the rocks by looking at their physical properties. (The properties or rocks include • Color • What mineral they are made of • Texture
The three main types of rocks are Igneous, Metamorphic, and Sedimentary.
Igneous rock Igneous rock forms from a red-hot mixture of melted minerals and gases.
Sedimentary Rock Forms in layers one layer at a time. Limestone is considered a sedimentary rock.
Metamorphic Rock Has been changed by heat, pressure, or both. This metamorphic rock is called gneiss.
Believe it or not, but all of these kinds of rocks are related. Their relationship to one another is called The Rock Cycle. Study the picture and see how one type of rock can be changed to another kind.
Igneous Rocks The formation of igneous rocks depends solely on magma. As you can see from this diagram, an oceanic plate drives itself underneath the continental plate. This is called a fault. The oceanic plate is more dense than the continental plate making it go underneath the lighter continental plate. The oceanic plate activates the zone of magma generation, causing it to come up through the Earth’s crust and create a volcano. The magma that reaches the surface is called lava, and when it cools, it forms igneous rock.
Here are some examples of igneous rocks. This igneous rock is called basalt. It is generally found on the surface of the Earth, composed of cooled lava. Granite is a common form of igneous rock found. Below is a picture of Granite in a close-up view.
Metamorphic Rocks Metamorphic rocks are rocks that were once of one kind but because of heat, pressure, or a chemical change, they were changed into something else. These rocks are called metamorphic rocks because they are “morphed,” or changed to a different kind of rock. The rocks could have been either igneous, sedimentary, or even another metamorphic rock to begin with. This rock is called granite. It is an igneous rock. Because of heat and pressure, it can be changed to a metamorphic rock called marble. This is what becomes Of granite when it is “morphed.” This is marble. This is a close-up of a section of marble rock.
Sedimentary Rocks Sedimentary rocks are made from other rocks that have been weathered. Weathering is the breaking down of rock pieces into smaller pieces. These small pieces of rock are then cemented together, compacted tightly, crystallized again to form new sedimentary rock. This is a close-up view of sandstone, a type of sedimentary rock. Notice the different colored particles that this rock is made up of. This gives the impression that it is made up of many different kinds of rock that have been broken down into small pieces and have been compacted tightly together.
Sedimentary rocks are often formed in layers. This occurs because the rocks were formed underwater. A river or stream picks up sediment along its path. When the river or stream drains into a large body of water, the sediment falls to the floor and accumulates. Different kinds of sediment are carried downstream at different times. This causes layers of different colored particles to accumulate.
Group Work Reclassify the rocks into the three main groups. (Igneous Rock, Sedimentary Rock, Metamorphic Rock.
Today you have learned about the rock cycle and some information about igneous, metamorphic, and sedimentary rocks. Use what you know about rocks and go out into the world and see if you can identify what kind of rocks are where.
Check Point • What are rocks made of?
You have found two rocks. One is gray, lightweight, and has lot of holes throughout. The other is heavy and mad up of pieces of different colors. Are these most likely the same king of rock.
Check Point • A rock collector shows you a rock changed by heat and pressure from another kind of rock deep inside the Earth. What kind of rock is it?
Two fossils are found in different layers of sedimentary rock. The rock layers have not been disturbed. Which is older the fossil in the lower layer or the one in the upper layers?
Foldable Create a foldable of the three main types of rocks.
Summary Summarize the three types of rocks.
