Download Chapter 7 Lesson 2 Notes

Chapter 7 Lesson 2
How Do Rocks Form?
Objectives:
1) Identify properties of rocks
2) Recognize the different types of rocks
3) Understand that rocks form slowly with time and pressure
Vocabulary:
1) rock: A natural substance made of one or more minerals
2) igneous rocks: Rocks that form when melted rock cools and
hardens
3) deposition: The process in which sediment settles out of water or is
dropped by wind
4) sedimentary rocks: Rocks formed when sediments are cemented
together
5) metamorphic rocks: Rocks formed when high heat and great
pressure change existing rocks into a new form.
Igneous Rocks
A _____________ is a _____________ solid made of one or
_____________ minerals. Most rocks are mixtures of minerals. Rocks are
classified into one or three forms dependent on how they _____________.
Rock that forms when _____________ rock _____________ and hardens is
called _____________ rock. These rocks can form _____________, or they
can form on Earth’s _____________.
Igneous rocks that form underground cool much more
_____________ than those that form on the surface. The rocks that are
formed below the ground hold in _____________ much longer than on the
surface. The rocks on the surface cool much more _____________ than
the ones below the surface.
Rocks are mixtures of minerals but the shape of the crystals is
different. When melted rock cools _____________, the crystals have time
to grow _____________. Igneous rocks that form _____________ have
_____________ crystals. When melted rock cools quickly, it _____________
before any crystals can grow large. Igneous rocks that form _____________
ground have little to no _____________.
The size of the crystal is not the only difference in _____________
rocks. Igneous rocks contain different amounts of _____________.
Identify me! Use the information on page 275 to identify the rocks.
1) I am cooled very slowly underground and have big mineral crystals. I
am sometimes used to make concrete. Who am I? _____________
2) I am the most common type of igneous rock. I form above the
surface where melted rock cools quickly and have small crystals.
Who am I? _____________
3) I am sometimes called volcanic glass. I am dark and shiny. Who am I?
_____________
4) I can be used to scrub and smooth skin! I have pores that are air
spaces making me really light. Who am I? _____________
Sedimentary Rocks
We have learned that rock gets worn away by many different things.
But, what happens to all the little pieces of rock, called _____________?
Sediment is carried off by _____________ or _____________. It is often set
down, or _____________, in another place. The process in which sediment
settles out of water or is dropped by wind is called _____________.
Over time, sediment piles up, building numerous layers , pressing
tightly together. Cemented sediment forms a type of rock called
_____________ rock. Sedimentary rocks form from any rock that is
_____________ down. Any sized _____________ can be found in sedimentary
rocks.
After _____________ rock forms, it might be _____________ away.
Sediment from the rock may be deposited in a different location in a
different way, forming a new sedimentary rock.
Identify me! Use the information on page 277 to identify the rocks.
1) I form in oceans from seashells. I can be found in abundance in
places such as Flordia and may be the cause of sinkholes. Who am I?
_____________
2) I am made up sediment the size of sand grains. Who am I?
_____________
3) I am a rock that is formed from different types of sediment. You
can find sand, pebbles, and other pieces of rock in me. Who am I?
_____________
4) I am made of dust sized particles/sediment. Who am I? _____________
Metamorphic Rocks
The process of when a caterpillar changes into a butterfly is called
_____________. This word comes from the Greek words, meta meaning
_____________, and morphe meaning _____________. Rocks can also change
under certain conditions. When a rock is changed by _____________ and
_____________, the new rock is called _____________ rock. These rocks can
form from any rock.
Metamorphic rocks are found in every _____________ range on
Earth. They can also be found on the ocean floor where new
_____________ is constantly being added. The layers stuck together by
minerals act as cement, becoming _____________ rock. In time, pressure
and heat is applied to these rocks changing them into _____________
rocks.
Identify Me! Use the information on page 279 to identify the rocks.
1) I come from calcite rich limestone and am often white. Who am I?
_____________
2) I may from sandstone found on mountains. Who am I? _____________
3) I too am formed from sandstone but am made of mostly quarz. Who
am I? _____________
4) I form when the igneous rock, granite receives a lot of pressure.
Who am I? _____________
Lesson 2: How Do Rocks Form?
In this lesson, you have learned that there are three groups of rock: igneous,
sedimentary, and metamorphic. You also learned that people use rocks in many
different ways.
1.
Focus Skill: Main Cause and Effect: Draw and complete a graphic
organizer that shows the causes of the way different rocks are formed.
2. Summarize: Write a one-paragraph summary of the way sedimentary
rocks form.
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3.
Draw Conclusions: You find an igneous rock with large crystals in it.
Where do you think the rock formed? Explain your answer.
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4.
Vocabulary: Write three sentences that describe the three main types
of rock. Give an example of each type.
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5. Test Prep: Critical Thinking: How can different kinds of igneous rocks
be classified?
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6. Test Prep: What kind of rock is gneiss?
A. igneous
C. metamorphic
B. marble
D. sedimentary
.