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Earths resources lessons 1 2 23 trang

Earth's
Resources
Lessons 1– 2

Grade 6
CA Unit 6

w w w.harcour tschool.com
ISBN-13: 978-0-15-349212-9
ISBN-10: 0-15-349212-0

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CXECA08ARD606_LLR_CVa.indd 2-3

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Think About the Reading
1. What can you do to help you remember what you have

learned about our resources?
2. What questions do you have after reading this book?
How can you find the answers to your questions?

Copyright © by Harcourt, Inc.
All rights reserved. No part of this publication may be reproduced or transmitted in
any form or by any means, electronic or mechanical, including photocopy, recording,
or any information storage and retrieval system, without permission in writing from the
publisher.
Requests for permission to make copies of any part of the work should be addressed to
School Permissions and Copyrights, Harcourt, Inc., 6277 Sea Harbor Drive, Orlando,
Florida 32887-6777. Fax: 407-345-2418.
HARCOURT and the Harcourt Logo are trademarks of Harcourt, Inc., registered in the
United States of America and/or other jurisdictions.

Hands-On Activity
Think about what you have learned about classifying material
resources. Create these charts and explain how they compare
and contrast.
1. Make a chart of renewable resources that you use in your
daily life
2. Make a chart of the non-renewable items that you use in
your daily life.

Printed in the United States of America
ISBN-13: 978-0-15-349212-9
ISBN-10: 0-15-349212-0
1 2 3 4 5 6 7 8 9 10

179

15 14 13 12 11 10 09 08 07 06

If you have received these materials as examination copies free of charge, Harcourt
School Publishers retains title to the materials and they may not be resold. Resale of
examination copies is strictly prohibited and is illegal.

Possession of this publication in print format does not entitle users to convert this
publication, or any portion of it, into electronic format.


CXECA08ARD606_LLR_CVa.indd 4-5

School-Home Connection
Discuss with a family member different energy resources that you
have learned about. Research with your family whether you live
near a type of energy plant that you have studied. What kind of
plant is it?

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Earth’ s
Resources
Lessons 1–2

Lesson 1
How Are Natural Resources Classified?. . . . . . . . . .2
Lesson 2
How Do Energy Resources Differ? . . . . . . . . . . . .10

Visit The Learning Site!
www.harcourtschool.com

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1
VOCABULARY
renewable
resource
nonrenewable
resource
fossil fuel

How Are
Natural
Resources
Classified?

The wind farm uses a
renewable resource. The wind
will blow again.

Once the coal is used up it is
gone and cannot be renewed.
Coal is a nonrenewable
resource.

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Coal is a fossil fuel we burn for energy.

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READING FOCUS SKILL
COMPARE AND CONTRAST
You compare things by looking for ways things are similar.
You contrast things by looking for the ways things are different.
Compare and contrast how renewable and nonrenewable
resources differ.

Renewable Resources
A natural resource is a material found in nature that is used to
meet a need. We use natural resources every day. Water is a natural
resource that we use for drinking, and cooking foods. A renewable
resource is always available. It can be replaced quickly through a
natural process. A renewable resource includes sunlight, air, fresh
water, and many kinds of plants and animals.

Water is a renewable resource.
It is renewed through the
water cycle.

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Young redwoods in a greenhouse
in Fort Bragg, California.

Some renewable resources are recycled through natural
processes. Plants and animals are renewable because they can
reproduce. Adult trees reproduce and the young trees grow. Natural
resources like these must be managed carefully.

Give one example of a natural renewable resource.

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Firewood is biomass,
a renewable energy.

Renewable Energy and Resources
Natural resources that people use to produce electricity are called
energy resources. Some energy resources can be replaced quickly.
A campfire is a form of fuel called biomass. Biomass is matter
from living things. Because biomass can grow back it is a renewable
energy resource.
Some energy resources are part of Earth’s crust. The heat from
this area can be used to warm homes and generate electricity.

The heat from Earth’s surface is
a renewable energy resource.

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Solar energy collects
energy from the sun.

Solar energy is a type of renewable energy. Solar cells can change
solar energy into electricity. The sun heats Earth’s atmosphere. This
can cause wind, which is also a renewable energy resource.

How is solar energy different from other renewable
energy resources?

Wind farms use wind to
produce electricity. Wind is a
renewable energy resource.

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Nonrenewable Resources
Not all of Earth’s resources are renewable. We call these resources
nonrenewable. A nonrenewable resource is a resource that
cannot be replaced.
The rain forest is an ecosystem. If it is destroyed it could take
hundreds of years to grow back. The rainforest is a nonrenewable
resource. If the forest is cut down or destroyed, the trees and
habitats are gone. Without a home the rainforest communities may
die out and never come back.
Rocks, minerals, soil and plants are all examples of resources that
cannot easily be replaced. Rocks for example may take millions of
years to travel through the rock cycle and form.

How is a nonrenewable resource different from a
renewable resource?

A rainforest is a nonrenewable
resource. It must be protected.

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Nonrenewable Energy Resources
A fossil fuel is an energy resource that cannot be replaced. Fossil
fuels formed from the remains of living things. This type of fuel
takes millions of years to form. So, when supplies are used up, there
will be no more left. Fossil fuel is a nonrenewable energy resource.
Coal, oil and natural gas are fossil fuels.
Uranium is a metal that is used in nuclear plants to produce
electricity. Uranium is a nonrenewable energy resource. Once all of
this metal is mined from Earth’s surface, no more can be made.

How are fossil fuels and uranium similar?

Coal comes from the
remains of plants that
died millions of years ago.

Review
Complete these compare and contrast statements.
1. A ______ ______ is always available and can be
replaced quickly.
2. A ______ ______ is a resource that cannot be replaced
easily/ There is a limited amount.
3. A ______ ______ is an energy resource that is formed
over millions of years. It comes from the buried
remains of living orgamisms.
4. Sun and water are ______ ______ that are always
available and can be quickly replaced.

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2
VOCABULARY
nuclear energy
radioactive
decay
hydroelectric
energy
geothermal
energy

How Do
Energy
Resources
Differ?

Nuclear energy can be
converted to electrical energy in
a nuclear reactor.

Some elements have radioactive
decay as thier atoms give off
particles.

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Water is converted to electricity through a
hydroelectric energy station.

This geothermal energy plant uses heat from
Earth to make electricity.

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READING FOCUS SKILL
COMPARE AND CONTRAST.
You compare things by looking for ways things are similar.
You contrast things by looking for the ways things are different.
Compare and contrast how energy resources are converted
into useful forms of energy.

Fossil Fuels
Useful energy resources are those that are not expensive and
which do not cause great harm to the environment. Currently, the
cheapest energy resources to use are fossil fuels.
Coal, oil, and natural gas are all fossil fuels. There are
environmental costs to using fossil fuels. Each of these fuels are taken
from Earth’s crust. The removal costs money. Air pollution is a cost
to people’s well-being and damages our environment.
Every energy resource has advantages and disadvantages.

What is an advantage to using fossil fuels?

Air pollution from burning fossil
fuels is a disadvantage to using
this energy resource.

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Nuclear fission occurs when
the nucleus of a uranium
atom is hit with a neutron.
The nucleus breaks, releasing
more neutrons. These
neutrons hit nuclei of other
uranium atoms, beginning a
chain reaction and releasing
energy!

Nuclear Energy
The nucleus of an atom contains two types of particles, protons
and neutrons. The energy that holds them together inside the
nucleus is called nuclear energy. Nuclear energy can be released in
two ways, by fission or fusion.
Nuclear fission is the breaking apart of one nucleaus into two
parts. Large atoms, such as uranium atoms can break easily. When
the split occurs a large amount of energy is released and a series of
reactions take place. This is called a chain reaction. Chain reactions
are used in power plants to create electricity.
Nuclear fusion can produce even more energy than fission.
However, scientists have not yet figured out a way to safely control
fusion reactions.

Why can’t we use nuclear fusion as a reliable energy
resource?
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Nuclear waste produced by nuclear
fission reactions is dangerous. It
must be stored in protected places.

Nuclear Energy Plants
Nuclear energy plants are very expensive to build. Yet, once built
they are inexpensive to run, because uranium cost less than fossil
fuels.
However, like fossil fuels, the use of nuclear energy has
environmental costs. These plants release heat into the air which
can be damaging. They produce a waste that goes through a
process called radioactive decay. Radioactive decay is the process
in which one element is transformed into another.

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Radioactive waste materials must be stored in special facilities.
The radiation from the deacy can cause illness in organisms.

What is a benefit to using nuclear energy plants?

Like fossil-fuel electric plants,
nuclear plants generate
heat. The heat is used to spin
turbines and make electricity.

Nuclear reactor core

Control rods

Generator

Turbine

Condenser

Heat exchanger

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Sun, Wind, and Water
Solar energy can be collected by using solar cells. A solar cell
becomes electrically charged when it absorbs light. Solar cells can
supply electricity to places that are far from electrical lines.
Solar energy is free, but solar cells are expensive to make. Many
places cannot rely on the sun for energy because they do not get
enough sunny days. Solar technology is inefficient.
Wind turbines are less expensive to make than solar cells but can
also be an inefficent energy source. If the wind is not blowing the
turbines on a certain day, electricity cannot be produced.

1. Water is
stored behind
the dam.
A hydroelectric dam
produces electricity.

2. When the gates
of the dam are
open, water pours
through a turbine.

3. The moving water turns the turbine, which
is connected by a shaft to a generator.
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Water is another renewable energy source like the sun and wind.
Electrical energy produced by moving water is called hydroelectric
energy. Most hydroelectric energy comes from dams across rivers.
Dams have environmental costs. They change upstream habitats and
decrease sediment. This can cause land to be less fertile and shrink.

Which is the most reliable source of energy, the sun,
wind, or water?

5. Wires carry the electric
current to homes and
businesses.

4. The rotation of a magnet
produces electric current in
the coils of the generator.

17

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Geothermal Energy
Energy that is generated from below Earth’s surface is called
geothermal energy. Recently technology has been created to use
geothermal energy.
One type of technology is deep-well drilling. Wells are dug deep
into the ground. Hot steam or ground water is pumped up to the
surface. The heat is used to turn turbines which is connected to
electric generators.
Geothermal energy is a clean energy source. However these
plants are only built near hot springs or hot spots. The waste from
these wells can cause air pollution.

How is a geothermal energy plant similar to other kinds
of energy plants?

A geothermal heat pump takes advantage of Earth’s crust temperature to
heat and cool a home.

During winter, cold air
from above ground is
pumped below ground,
where the air is warmed.
The warm air is then
pumped up into the house.

During summer,
warm air from
above ground is
pumped below
ground, where
the air is cooled.
Then the cool air
is pumped into the
house.

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Energy Resources

Fossil fuels
Geothermal energy

Solar energy

Nuclear energy

Biomass

Hydroelectric energy

Wind energy

Review
Complete these compare and contrast statements.
1. The cheapest from of energy that we use today
is ______ ______ .
2. ______ ______ is produced in the splitting of a nucleus
during nuclear fission.
3. ______ ______ is electrical energy produced by
moving water.
4. Energy generated from hot water or steam below
Earth’s surface is called ______ ______ .

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GLOSSARY
fossil fuel [FAHS•uhl FYOO•uhl] Coal and petroleum that were
formed from ancient organisms.
geothermal energy [jee•oh•THER•muhl EN•er•jee] Energy
produced from within Earth’s crust.
hydroelectric energy [hy•droh•ee•LEK•trik EN•er•jee] Electricity
produced by moving water.
nonrenewable resource [nahn•rih•NOO•uh•buhl REE•sawrs] A
resource that cannot be replaced quickly if it is used up.
nuclear energy [NOO•klee•er EN•er•jee] The energy that binds
protons and neutrons inside an atom’s nucleus.
radioactive decay [ray•dee•oh•AK•tiv dee•KAY] The process by
which the nuclei of atoms give off particles.
renewable resource [rih•noo•uh•buhl REE•sawrs] A resource
that can be replaced quickly through natural processes.

20

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Think About the Reading
1. What can you do to help you remember what you have
learned about our resources?
2. What questions do you have after reading this book?
How can you find the answers to your questions?

Copyright © by Harcourt, Inc.
All rights reserved. No part of this publication may be reproduced or transmitted in
any form or by any means, electronic or mechanical, including photocopy, recording,
or any information storage and retrieval system, without permission in writing from the
publisher.
Requests for permission to make copies of any part of the work should be addressed to
School Permissions and Copyrights, Harcourt, Inc., 6277 Sea Harbor Drive, Orlando,
Florida 32887-6777. Fax: 407-345-2418.
HARCOURT and the Harcourt Logo are trademarks of Harcourt, Inc., registered in the
United States of America and/or other jurisdictions.

Hands-On Activity
Think about what you have learned about classifying material
resources. Create these charts and explain how they compare
and contrast.
1. Make a chart of renewable resources that you use in your
daily life
2. Make a chart of the non-renewable items that you use in
your daily life.

Printed in the United States of America
ISBN-13: 978-0-15-349212-9
ISBN-10: 0-15-349212-0
1 2 3 4 5 6 7 8 9 10

179

15 14 13 12 11 10 09 08 07 06

If you have received these materials as examination copies free of charge, Harcourt
School Publishers retains title to the materials and they may not be resold. Resale of
examination copies is strictly prohibited and is illegal.

Possession of this publication in print format does not entitle users to convert this
publication, or any portion of it, into electronic format.

CXECA08ARD606_LLR_CVa.indd 4-5

School-Home Connection
Discuss with a family member different energy resources that you
have learned about. Research with your family whether you live
near a type of energy plant that you have studied. What kind of
plant is it?

2/20/06 4:48:51 PM



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