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Tiêu đề Science Grade 6 Level Red
Trường học The McGraw-Hill Companies, Inc.
Chuyên ngành Science
Thể loại textbook
Năm xuất bản 2005
Thành phố Columbus
Định dạng
Số trang 799
Dung lượng 94,2 MB

Nội dung

Sách cambrige science khối 6 level red national georaphic, Sách cambrige science khối 6 level red national georaphic, Sách cambrige science khối 6 level red national georaphic Sách cambrige science khối 6 level red national georaphic

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Level Red

The cover shows the Colorado

River in the Grand Canyon

It is the primary river of the

American Southwest This

forked lightning bolt shows a

large static discharge between

the dark clouds and the ground

This red-eyed tree frog can be

found in rain forests in South

and Central America, and as far

of the publisher.

The National Geographic features were designed and developed by the National Geographic Society’s Education Division Copyright © National Geographic Society.The name “National Geographic Society” and the Yellow Border Rectangle are trademarks of the Society, and their use, without prior written permission, is strictly prohibited.

The “Science and Society” and the “Science and History” features that appear in this book were designed and developed by TIME School Publishing, a division of TIME Magazine.TIME and the red border are trademarks of Time Inc All rights reserved.

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The Nature of Matter 2

Chapter 1 The Nature of Science 4

Chapter 2 Measurement 40

Chapter 3 Matter and Its Changes 68

Chapter 4 Atoms, Elements, and the Periodic Table 96

Interactions of Matter 126

Chapter 5 Motion, Forces, and Simple Machines 128

Chapter 6 Energy 160

Chapter 7 Electricity and Magnetism 192

Chapter 8 Waves 224

Earth’s Changing Surface 252

Chapter 9 Rocks and Minerals 254

Chapter 10 Forces Shaping Earth 286

Chapter 11 Weathering and Erosion 314

Chapter 12 The Atmosphere in Motion 340

Chapter 13 Oceans 372

Beyond Earth 404

Chapter 14 Exploring Space 406

Chapter 15 The Solar System and Beyond 438

Life’s Diversity 472

Chapter 16 Cells—The Units of Life 474

Chapter 17 Invertebrate Animals 496

Chapter 18 Vertebrate Animals 528

Chapter 19 The Human Body 558

Chapter 20 The Role of Genes in Inheritance 588

Life and the Environment 614

Chapter 21 Ecology 616

Chapter 22 Earth’s Resources 644

Contents

In Brief

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Alton J Banks, PhD

Director of the Faculty Center for Teaching and Learning North Carolina State University

Jerome A Jackson, PhD

Whitaker Eminent Scholar in Science

Program Director Center for Science, Mathematics, and Technology Education Florida Gulf Coast University Fort Meyers, FL

William C Keel, PhD

Department of Physics and Astronomy University of Alabama Tuscaloosa, AL

New York, NY

Authors

Series Consultants

Education Division Washington, D.C.

Alton BiggsRetired Biology Teacher Allen High School Allen, TXLucy Daniel, PhDTeacher/Consultant Rutherford County Schools Rutherfordton, NCRalph M Feather Jr., PhD

Assistant Professor Geoscience Department Indiana University of Pennsylvania

Indiana, PA

Edward OrtlebScience Consultant

St Louis, MOSusan Leach SnyderRetired Teacher, Consultant Jones Middle School Upper Arlington, OHDinah ZikeEducational Consultant Dinah-Might Activities, Inc.

San Antonio, TX

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Dominic Salinas, PhD

Middle School Science Supervisor Caddo Parish Schools Shreveport, LA

Cheryl Wistrom

St Joseph’s College Rensselaer, IN

Carl Zorn, PhD

Staff Scientist Jefferson Laboratory Newport News, VA

MATH

Michael Hopper, DEng

Manager of Aircraft Certification L-3 Communications Greenville, TX

Teri Willard, EdD

Mathematics Curriculum Writer

Barry Barto

Special Education Teacher John F Kennedy Elementary Manistee, MI

Carol A Senf, PhD

School of Literature, Communication, and Culture Georgia Institute of Technology

Atlanta, GA

Rachel Swaters-Kissinger

Science Teacher John Boise Middle School Warsaw, MO

SAFETY

Aileen Duc, PhD

Science 8 Teacher Hendrick Middle School, Plano ISD

Plano, TX

Sandra West, PhD

Department of Biology Texas State University-San Marcos

San Marcos, TX

ACTIVITY TESTERS

Nerma Coats Henderson

Pickerington Lakeview Jr High

School Pickerington, OH

Mary Helen Mariscal-Cholka

William D Slider Middle School

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Anthony J DiSipio, Jr.

8th Grade Science Octorana Middle School Atglen, PA

George Gabb

Great Bridge Middle School Chesapeake Public Schools Chesapeake, VA

Annette D’Urso Garcia

Kearney Middle School Commerce City, CO

Nerma Coats Henderson

Pickerington Lakeview Jr.

High School Pickerington, OH

Burke, VA

Michael Mansour

Board Member National Middle Level Science Teacher’s Association John Page Middle School Madison Heights, MI

Mary Helen Mariscal-Cholka

William D Slider Middle School

Norma Neely, EdD

Associate Director for Regional

Projects Texas Rural Systemic Initiative

Austin, TX

Annette Parrott

Lakeside High School Atlanta, GA

Nora M Prestinari Burchett

Saint Luke School McLean, VA

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on the content and design of the Student Edition They provided valuable input in the

development of the 2005 edition of Glencoe Science Level Red.

Teacher Advisory Board

The Glencoe middle school science Student Advisory Board taking a timeout at COSI,

a science museum in Columbus, Ohio.

on the design of the Student Edition We thank these students for their hard work and

creative suggestions in making the 2005 edition of Glencoe Science Level Red student

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Why do I need

my science book?

Have you ever been in class and

not understood all of what was

presented? Or, you understood

everything in class, but at home,

got stuck on how to answer a

question? Maybe you just

wondered when you were ever

going to use this stuff?

These next few pages

are designed to help you

understand everything your

science book can be used

for besides a paperweight!

Before You Read

Chapter Opener Science is occurring all around you,and the opening photo of each chapter will preview the

science you will be learning about The Chapter

Preview will give you an idea of what you will be

learning about, and you can try the Launch Lab to

help get your brain headed in the right direction The

Foldables exercise is a fun way to keep you organized.

Section Opener Chapters are divided into two to four

sections The As You Read in the margin of the first

page of each section will let you know what is mostimportant in the section It is divided into four parts

What You’ll Learn will tell you the major topics you

will be covering Why It’s Important will remind you

why you are studying this in the first place! The

Review Vocabulary word is a word you already know,

either from your science studies or your prior

knowl-edge The New Vocabulary words are words that you

need to learn to understand this section These words

will be in boldfaced print and highlighted in the

section Make a note to yourself to recognize thesewords as you are reading the section

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As You Read

Headings Each section has a title

in large red letters, and is furtherdivided into blue titles andsmall red titles at the begin-nings of some paragraphs

To help you study, make anoutline of the headings andsubheadings

Margins In the margins ofyour text, you will find many helpful

resources The Science Online exercises and

Integrate activities help you explore the topics

you are studying MiniLabs reinforce the

sci-ence concepts you have learned

Building Skills You also will find an

Applying Math or Applying Science activity

in each chapter This gives you extra tice using your new knowledge, and helpsprepare you for standardized tests

prac-● Student Resources At the end of the book

you will find Student Resources to help you

throughout your studies These include

Science, Technology, and Math Skill books, an English/Spanish Glossary, and an Index Also, use your Foldables as a resource.

Hand-It will help you organize information, andreview before a test

In Class Remember, you can always

ask your teacher to explain anything you don’t understand

Science Vocabulary Make the following Foldable to help you understand the vocabulary terms in this chapter.

Fold a vertical sheet of notebook paper from side to side.

Cut along every third line of only the top layer to form tabs.

Label each tab with a vocabulary word from the chapter.

Build Vocabulary As you read the chapter, list the vocabulary words on the tabs As you learn the definitions, write them under the tab for each vocabulary word.

STEP 3

STEP 2 STEP 1

ix

Look For

At the beginning of every section

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In Lab

Working in the laboratory is one of the best ways to understand the cepts you are studying Your book will be your guide through your laboratoryexperiences, and help you begin to think like a scientist In it, you not only willfind the steps necessary to follow the investigations, but you also will findhelpful tips to make the most of your time

con-● Each lab provides you with a Real-World Question to remind you that

science is something you use every day, not just in class This may lead

to many more questions about how things happen in your world

● Remember, experiments do not always produce the result you expect

Scientists have made many discoveries based on investigations with pected results You can try the experiment again to make sure your resultswere accurate, or perhaps form a new hypothesis to test

unex-● Keeping a Science Journal is how scientists keep accurate records of

obser-vations and data In your journal, you also can write any questions thatmay arise during your investigation This is a great method of remindingyourself to find the answers later

Look For

Launch Labsstart every chapter.

MiniLabsin the margin of each

chapter

Two Full-Period Labs

in everychapter

EXTRA Try at Home Labs

at the

end of your book

● the Web sitewith

laboratory

demonstrations.

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Before a Test

Admit it! You don’t like to take tests! However, there are

ways to review that make them less painful Your book willhelp you be more successful taking tests if you use theresources provided to you

Review all of the New Vocabulary words and be sure you

understand their definitions

Review the notes you’ve taken on your Foldables, in class,

and in lab Write down any question that you still needanswered

Review the Summaries and Self Check questions at the

end of each section

● Study the concepts presented in the chapter by reading

the Study Guide and answering the questions in the Chapter Review.

● the Study Guideand Review

at the end of each chapter

● the Standardized Test Practice

after each chapter

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Let’s Get Started

To help you find the information you need quickly, use the Scavenger Hunt below to learn where things are located in Chapter 1.

What is the title of this chapter?

What will you learn in Section 1?

Sometimes you may ask, “Why am I learning this?” State a reason why the concepts from Section 2 are important

What is the main topic presented in Section 2?

How many reading checks are in Section 1?

What is the Web address where you can find extra information?

What is the main heading above the sixth paragraph in Section 2?

There is an integration with another subject mentioned in one of the margins

of the chapter What subject is it?

List the new vocabulary words presented in Section 2

List the safety symbols presented in the first Lab

Where would you find a Self Check to be sure you understand the section?

Suppose you’re doing the Self Check and you have a question about concept mapping Where could you find help?

On what pages are the Chapter Study Guide and Chapter Review?

Look in the Table of Contents to find out on which page Section 2 of the chapter begins

You complete the Chapter Review to study for your chapter test

Where could you find another quiz for more practice?

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Contents

In each chapter, look for these opportunities for review and assessment:

• Reading Checks

• Caption Questions

• Section Review

• Chapter Study Guide

• Chapter Review

• Standardized Test Practice

• Online practice at

red.msscience.com

The Nature of Matter—2

The Nature of Science—4

Section 1 What is science? 6

Section 2 Science in Action 12

Section 3 Models in Science 21

Section 4 Evaluating Scientific Explanation 27

Lab What is the right answer? 31

Lab Identifying Parts of an Investigation 32

Measurement—40 Section 1 Description and Measurement 42

Section 2 SI Units 50

Lab Scale Drawing 55

Section 3 Drawings, Tables, and Graphs 56

Lab: Design Your Own Pace Yourself 60

Matter and its Changes—68 Section 1 Physical Properties and Changes 70

Section 2 Chemical Properties and Changes 80

Lab Liquid Layers 87

Lab: Design Your Own Fruit Salad Favorites 88

Atoms, Elements, and the Periodic Table—96 Section 1 Structure of Matter 98

Section 2 The Simplest Matter 106

Lab Elements and the Periodic Table 112

Section 3 Compounds and Mixtures 113

Lab Mystery Mixture 118

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Interactions of Matter—126

Motion, Forces, and Simple Machines—128

Section 1 Motion 130

Section 2 Newton’s Laws of Motion 136

Section 3 Work and Simple Machines 144

Lab Motion 151

Lab: Use the Internet Methods of Travel 152

Energy—160 Section 1 Energy Changes 162

Section 2 Temperature 170

Section 3 Chemical Energy 178

Lab Converting Potential and Kinetic Energy 183 Lab Comparing Temperature Changes 184

Electricity and Magnetism—192 Section 1 Electric Charge and Forces 194

Section 2 Electric Current 201

Section 3 Magnetism 209

Lab Batteries in Series and Parallel 215

Lab Magnets and Electric Current 216

Waves—224 Section 1 What are waves? 226

Section 2 Wave Properties 231

Lab Waves on a Spring 236

Section 3 Wave Behavior 237

Lab: Design Your Own

In each chapter, look for these opportunities for review and assessment:

• Reading Checks

• Caption Questions

• Section Review

• Chapter Study Guide

• Chapter Review

• Standardized Test Practice

• Online practice at

red.msscience.com

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xv

Earth’s Changing Surface—252

Rocks and Minerals—254

Section 1 Minerals—Earth’s Jewels 256

Section 2 Igneous and Sedimentary Rocks 265

Section 3 Metamorphic Rocks and the Rock Cycle 272

Lab Gneiss Rice 277

Lab Classifying Materials 278

Forces Shaping Earth—286 Section 1 Earth’s Moving Plates 288

Lab Earth’s Moving Plates 298

Section 2 Uplift of Earth’s Crust 299

Lab: Model and Invent Isostasy 306

Weathering and Erosion—314 Section 1 Weathering and Soil Formation 316

Lab Classifying Soils 322

Section 2 Erosion of Earth’s Surface 323

Lab: Design Your Own Measuring Soil Erosion 332

The Atmosphere in Motion—340 Section 1 The Atmosphere 342

Section 2 Earth’s Weather 348

Section 3 Air Masses and Fronts 356

Lab Interpreting Satellite Images 363

Lab: Design Your Own Creating Your Own Weather Station 364

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Oceans—372

Section 1 Ocean Water 374

Lab Desalination 379

Section 2 Ocean Currents and Climate 380

Section 3 Waves 385

Section 4 Life in the Oceans 389

Lab: Model and Invent Waves and Tides 396

Beyond Earth—404 Exploring Space—406 Section 1 Radiation from Space 408

Lab Building a Reflecting Telescope 414

Section 2 Early Space Missions 415

Section 3 Current and Future Space Missions 423

Lab: Use the Internet Star Sightings 430

The Solar System and Beyond—438 Section 1 Earth’s Place in Space 440

Lab Moon Phases 447

Section 2 The Solar System 448

Section 3 Stars and Galaxies 456

Lab: Design Your Own Space Colony 464

In each chapter, look for these opportunities for review and assessment:

• Reading Checks

• Caption Questions

• Section Review

• Chapter Study Guide

• Chapter Review

• Standardized Test Practice

• Online practice at

red.msscience.com

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Contents

Life’s Diversity—472

Cells–The Units of Life—474

Section 1 The World of Cells 476

Lab Observing Algae 482

Section 2 The Different Jobs of Cells 483

Lab: Design Your Own Water Movement in Plants 488

Invertebrate Animals—496 Section 1 What is an animal? 498

Section 2 Sponges, Cnidarians, Flatworms, and Roundworms 501

Section 3 Mollusks and Segmented Worms 506

Section 4 Arthropods and Echinoderms 512

Lab Observing Complete Metamorphosis 519

Lab: Design Your Own Garbage-Eating Worms 520

Vertebrate Animals—528 Section 1 Chordate Animals 530

Section 2 Amphibians and Reptiles 535

Lab Frog Metamorphosis 540

Section 3 Birds 541

Section 4 Mammals 545

Lab: Model and Invent Homes for Endangered Animals 550

The Human Body—558 Section 1 Body Systems 560

Lab Improving Reaction Time 573

Section 2 Human Reproduction 574

Lab: Design Your Own Defensive Saliva 580

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The Role of Genes in Inheritance—588

Section 1 Continuing Life 590

Lab Getting DNA from Onion Cells 598

Section 2 Genetics—The Study of Inheritance 599

Lab: Use the Internet Genetic Traits: The Unique You 606

Life and the Environment—614 Ecology—616 Section 1 What is an ecosystem? 618

Lab Ecosystem in a Bottle 626

Section 2 Relationships Among Living Things 627

Section 3 Energy Through the Ecosystem 633

Lab: Design Your Own What’s the limit? 636

Earth’s Resources—644 Section 1 Natural Resource Use 646

Lab Using Water 654

Section 2 People and the Environment 655

Section 3 Protecting the Environment 663

Lab: Design Your Own Using Land 668

In each chapter, look for these opportunities for review and assessment:

• Reading Checks

• Caption Questions

• Section Review

• Chapter Study Guide

• Chapter Review

• Standardized Test Practice

• Online practice at

red.msscience.com

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Contents

Student Resources—676

Science Skill Handbook—678

Scientific Methods 678

Safety Symbols 687

Safety in the Science Laboratory 688

Extra Try at Home Labs—690 Technology Skill Handbook—701 Computer Skills 701

Presentation Skills 704

Math Skill Handbook—705 Math Review 705

Science Applications 715

Reference Handbooks—720 Periodic Table of the Elements 720

Topographic Map Symbols 722

Rocks 723

Minerals 724

Diversity of Life: Classification of Living Organisms 726

Use and Care of a Microscope 730

English/Spanish Glossary—731 Index—750

Credits—769

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Cross-Curricular Readings

Unit Openers

Unit 1 How are Arms and Centimeters Connected? 2

Unit 2 How are Train Schedules and Oil Pumps Connected? 126

Unit 3 How are Rocks and Fluorescent Lights Connected? 252

Unit 4 How are the Inuit and Astronauts Connected? 404

Unit 5 How are Animals and Airplanes Connected? 472

Unit 6 How are Oatmeal and Carpets Connected? 614

VISUALIZING 1 The Modeling of King Tut 24

2 Precision and Accuracy 46

3 Dichotomous Keys 78

4 The Periodic Table 108

5 Newton’s Laws and Space Travel 142

6 Kinetic Energy 165

7 Batteries 206

8 Interference 242

9 Igneous Rock Features 268

10 Rift Valleys 294

11 Mass Movements 324

12 The Water Cycle 346

13 Food Chains in a Food Web 393

14 Space Probes 419

15 Galaxies 460

16 Life’s Organization 486

17 Arthropod Diversity 514–515 18 Fish Diversity 533

19 Vitamins 565

20 Human Reproduction 596

21 Biotic Factors 621

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6 “Hiroshima” 186

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11 Water’s Force 315

available as a video lab

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3 Observing Yeast 84

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Content Details

2 Pace Yourself 60–61

The Unique You 606–607

Use the Internet Labs Model and Invent Labs Design Your Own Labs Two-Page Labs

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16 Red Blood Cells 485

20 Alleles in Sex Cells 603

22 Reusing Plastic 665

Applying Science Applying Math

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Standardized Test Practice

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Visit to find project ideas and resources.

Projects include:

• History Brainstorm characteristics of science fields, and then design a collage with science ideas for a ceiling tile or book cover.

• Technology Convert a family recipe from English measurement to SI units

of measurement Enjoy a classroom bake-off!

• Model Create a character in an SI world Develop a picture storybook or comic book to demonstrate your knowledge of SI measurement.

The Nature of Science: Evaluating Bias in Advertisementshelps students to become informed about the techniques of advertising and evaluate bias in print media.

red.msscience.com/unit_project

About 5,000 years ago, the Egyptians developed one of the earliest recorded units of measurement—the cubit, which was based on the length of the arm from elbow to fingertip The Egyptian measurement system probably influenced later systems, many of which also were based on body parts such as arms and feet Such systems, however, could be problematic, since arms and feet vary in length from one person to another Moreover, each country had its own system, which made it hard for people from different countries to share information The need for a precise, universal measurement system eventually led to the adoption

of the meter as the basic international unit of length A meter is defined as the distance that light travels in a vacuum in a certain fraction of a second—a distance that never varies Meters are divided into smaller units called centimeters, which are seen on the rulers here.

3

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1 What is science?

2 Science in Action

3 Models in Science

4 Evaluating Scientific Explanation

Lab What is the right answer?

Lab Identifying Parts of an Investigation

Virtual Lab How is a controlled

experiment performed?

How is science a par t

of your ever yday life?

Scientists studying desert ecosystems inCalifornia wondered how such a dry environ-ment could produce such beautiful, prolificflowers Scientists began asking questions andperforming investigations

Write down three examples ofscience in your everyday life

Science Journal

The Nature

of Science

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Science Make the following Foldable to help identify what you already know, what you want to know, and what you learned about science.

Fold a vertical sheet

of paper from side to side Make the front edge about 1/2 inch shorter than the back edge.

Turn lengthwise and fold into thirds.

Unfold and cut only the top layer along both folds to make three tabs Label each tab.

Identify Questions Before you read the ter, write what you already know about science under the left tab of your Foldable, and write questions about what you’d like to know under the center tab After you read the chapter, list what you learned under the right tab.

chap-STEP 3 STEP 2

in action scientists can study nature

Perform the lab below to see how gravityaffects objects

1. Collect three identical, unsharpenedpencils

2. Tape two of the pencils together

3. Hold all the pencils at the same height ashigh as you can Drop them together andobserve what happens as they fall

4 Think Critically Did the single pencil fallfaster or slower than the pair? Predict inyour Science Journal what would happen

if you taped 30 pencils together anddropped them at the same time as youdropped a single pencil

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Learning About the World

When you think of a scientist, do you imagine a person in alaboratory surrounded by charts, graphs, glass bottles, and bub-bling test tubes? It might surprise you to learn that anyone whotries to learn something about the natural world is a scientist

Science is a way of learning more about the natural world.

Scientists want to know why, how, or when something occurred.This learning process usually begins by keeping your eyes openand asking questions about what you see

Asking Questions Scientists ask many questions How dothings work? What do things look like? What are they made of?Why does something take place? Science can attempt to answermany questions about the natural world, but some questions can-

Who should you vote for? What does this poem mean? Who isyour best friend? Questions about art, politics, personal prefer-ence, or morality can’t be answered by science Science can’t tellyou what is right, wrong, good, or bad

What is science?

Definescience and identify

ques-tions that science cannot answer.

Compareand contrast theories

Science can be used to learn more

about the world you live in.

Review Vocabulary

theory: explanation of things or

events that is based on

knowl-edge gained from many

observa-tions and experiments

New Vocabulary

•science •life science

•scientific •Earth science

theory •physical

•scientific law science

•system •technology

Figure 1 Questions

about politics, literature,

and art cannot be answered

by science.

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SECTION 1 What is science? 7

Question

Possible outcomes

One explanation

Explanation still possible

Explanation modified

Explanation discarded

New possible explanation

New information

Figure 2 As new information becomes available, explanations can be modified or discarded and new explanations can be made

Possible Explanations If learning about your world beginswith asking questions, can science provide answers to thesequestions? Science can answer a question only with the informa-tion available at the time Any answer is uncertain because peo-ple will never know everything about the world around them

With new knowledge, they might realize that some of the oldexplanations no longer fit the new information As shown in

Figure 2,some observations might force scientists to look at oldideas and think of new explanations Science can only providepossible explanations

Why can’t science answer questions with certainty?

Scientific Theories An attempt to explain a pattern

observed repeatedly in the natural world is called a scientific

theory Theories are not simply guesses or someone’s opinions,

nor are theories vague ideas Theories in science must be ported by observations and results from many investigations

sup-They are the best explanations that have been found so far

However, theories can change As new data become available,scientists evaluate how the new data fit the theory If enoughnew data do not support the theory, the theory can be changed

to fit the new observations better

Scientific Laws A rule that describes a pattern in nature is a

scientific law For an observation to become a scientific law, it

must be observed repeatedly The law then stands until someonemakes observations that do not follow the law A law helps youpredict that an apple dropped from arm’s length will always fall

to Earth The law, however, does not explain why gravity exists

or how it works A law, unlike a theory, does not attempt toexplain why something happens It simply describes a pattern

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Systems in Science

Scientists can study many different things in nature Somemight study how the human body works or how planets movearound the Sun Others might study the energy carried in a light-ning bolt What do all of these things have in common? All of

them are systems A system is a collection of structures, cycles,

and processes that relate to and interact with each other Thestructures, cycles, and processes are the parts of a system, just likeyour stomach is one of the structures of your digestive system

What is a system?

Systems are not found just in science Your school is a systemwith structures such as the school building, the tables andchairs, you, your teacher, the school bell, your pencil, and many

school day also has cycles Your daily class schedule and the endar of holidays are examples of cycles Many processes are atwork during the school day When you take a test, your teacherhas a process You might be asked to put your books and papersaway and get out a pencil before the test is distributed When thetime is over, you are told to put your pencil down and pass yourtest to the front of the room

cal-Parts of a System Interact In a system, structures, cycles,and processes interact Your daily schedule influences where you

go and what time you go The clock shows the teacher when thetest is complete, and you couldn’t complete the test without apencil

Figure 3 Systems are a

collection of structures, cycles,

and processes.

Infer What systems can you

identify in this classroom?

Classifying Parts

of a System

Procedure

Think about how your school’s

cafeteria is run Consider the

physical structure of the

cafe-teria How many people run

it? Where does the food come

from? How is it prepared?

Where does it go? What other

parts of the cafeteria system

are necessary?

Analysis

Classify the parts of your

school cafeteria’s system as

structures, cycles,

or processes.

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SECTION 1 What is science? 9

Parts of a Whole All systems are made up of other systems

For example, you are part of your school The human body is asystem—within your body are other systems Your school is part

of a system—district, state, and national You have your regionalschool district Your district is part of a statewide school system

Scientists often break down problems by studying just one part

of a system A scientist might want to learn about how tion of buildings affects the ecosystem Because an ecosystemhas many parts, one scientist might study a particular animal,and another might study the effect of construction on plant life

construc-The Branches of Science

Science often is divided into three main categories, orbranches—life science, Earth science, and physical science Eachbranch asks questions about different kinds of systems

Life Science The study of living systems and the ways in

which they interact is called life science Life scientists attempt

to answer questions like “How do whales navigate the ocean?”

and “How do vaccines prevent disease?” Life scientists can studyliving organisms, where they live, and how they interact Dian

habitat, and their behaviors

People who work in the health field know a lot about the lifesciences Physicians, nurses, physical therapists, dietitians, medicalresearchers, and others focus on the systems of the human body

Some other examples of careers that use life science include ogists, zookeepers, botanists, farmers, and beekeepers

biol-Figure 4 Over a span of

18 years, life scientist Dian Fossey spent much of her time observing mountain gorillas in Rwanda, Africa She was able to interact with them as she learned about their behavior.

Health Integration Systems The human body

is composed of many ent systems that all inter-act with one another toperform a function Theheart is like the controlcenter Even though not allsystems report directly tothe heart, they all interactwith its function If theheart is not working, theother systems fail as well.Research human body sys-tems and explain how onesystem can affect another

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differ-Figure 5 These volcanologists

are studying the temperature of

the lava flowing from a volcano.

Earth Science The study of Earth systems and the systems in

space is Earth science It includes the study of nonliving things

such as rocks, soil, clouds, rivers, oceans, planets, stars, meteors,and black holes Earth science also covers the weather and cli-mate systems that affect Earth Earth scientists ask questions like

“How can an earthquake be detected?” or “Is water found onother planets?” They make maps and investigate how geologicfeatures formed on land and in the oceans They also use theirknowledge to search for fuels and minerals Meteorologists studyweather and climate Geologists study rocks and geologic fea-

vol-canoes—measuring the temperature of lava

What do Earth scientists study?

Physical Science The study of matter and energy is

physical science Matter is anything that takes up space and

has mass The ability to cause change in matter is energy.Living and nonliving systems are made of matter Examplesinclude plants, animals, rocks, the atmosphere, and the water

in oceans, lakes, and rivers Physical science can be dividedinto two general fields—chemistry and physics Chemistry isthe study of matter and the interactions of matter Physics isthe study of energy and its ability to change matter Figure 6shows physical scientists at work

This chemist is studying the light emitted by certain compounds.

This physicist is studying light as

it travels through optical fibers.

Figure 6 Physical scientists

study a wide range of subjects.

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SECTION 1 What is science? 11

• Scientists ask questions to learn how, why, or when something occurred.

• A theory is a possible explanation for tions that is supported by many investigations.

observa-• A scientific law describes a pattern but does not explain why things happen

Systems in Science

• A system is composed of structures, cycles, and processes that interact with each other.

The Branches of Science

• Science is divided into three branches—life science, Earth science, and physical science.

• Technology is the application of science in our everyday lives.

5 Infer Scientists ask questions and make observations What types of questions and observations would you make if you were a scientist studying schools of fish in the ocean.

Careers Chemists ask questions such as “Howcan I make plastic stronger?” or “What can I do tomake aspirin more effective?” Physicists mightask other types of questions, such as “How doeslight travel through glass fibers?” or “How canhumans harness the energy of sunlight for theirenergy needs?”

Many careers are based on the physical ences Physicists and chemists are some obviouscareers Ultrasound and X-ray technicians work-ing in the medical field study physical science becausethey study the energy in ultrasound or X rays and how itaffects a living system

sci-Science and Technology Although learning theanswers to scientific questions is important, theseanswers do not help people directly unless they can be

applied in some way Technology is the practical use of

apply science to develop technology The study of how to use theenergy of sunlight is science Using this knowledge to createsolar panels is technology The study of the behavior of light as

it travels through thin, glass, fiber-optic wires is science The use

of optical fibers to transmit information is technology A tist uses science to study how the skin of a shark repels water

scien-The application of this knowledge to create a material that helpsswimmers slip through the water faster is technology

Figure 7 Solar-powered cars and the swimsuits worn in the Olympics are examples of technol- ogy—the application of science.

red.msscience.com/self_check_quiz

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Science Skills

You know that science involves asking questions, but howdoes asking questions lead to learning? Because no single way togain knowledge exists, a scientist doesn’t start with step one,then go to step two, and so on Instead, scientists have a hugecollection of skills from which to choose Some of these skillsinclude thinking, observing, predicting, investigating, research-ing, modeling, measuring, analyzing, and inferring Science alsocan advance with luck and creativity

Science Methods Investigations often follow a general

see-ing somethsee-ing and then asksee-ing a question about what wasobserved Scientists often perform research by talking with otherscientists They read books and scientific magazines to learn asmuch as they can about what is already known about their ques-tion Usually, scientists state a possible explanation for theirobservation To collect more information, scientists almostalways make more observations They might build a model ofwhat they study or they might perform investigations Often,they do both How might you combine some of these skills in aninvestigation?

Identifysome skills scientists use.

Definehypothesis.

Recognizethe difference between

observation and inference.

Science can be used to learn more

about the world you live in.

Review Vocabulary

observation: a record or

descrip-tion of an occurrence or pattern in

Repeat several times

Hypothesis not supported

Modify hypothesis

Figure 8 Although there are

differ-ent scidiffer-entific methods for investigating

a specific problem, most investigations

follow a general pattern.

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SECTION 2 Science in Action 13

Questioning and Observing Ms Clark placed a sealed shoebox on the table at the front of the laboratory Everyone in theclass noticed the box Within seconds the questions flew

“What’s in the box?” “Why is it there?”

Ms Clark said she would like the class to see how they usedsome science skills without even realizing it

“I think that she wants us to find out what’s in it,” Isabellesaid to Marcus

“Can we touch it?” asked Marcus

“It’s up to you,” Ms Clark said

Marcus picked up the box and turned it over a few times

“It’s not heavy,” Marcus observed “Whatever is inside slidesaround.” He handed the box to Isabelle

Isabelle shook the box The class heard the object strike thesides of the box With every few shakes, the class heard a metal-lic sound The box was passed around for each student to makeobservations and write them in his or her Science Journal Some

Taking a Guess “I think it’s a pair of scissors,” said Marcus

“Aren’t scissors lighter than this?” asked Isabelle, while ing the box “I think it’s a stapler.”

shak-“What makes you think so?” asked Ms Clark

“Well, staplers are small enough to fit inside a shoe box, and

it seems to weigh about the same,” said Isabelle

“We can hear metal when we shake it,” said Enrique

“So, you are guessing that a stapler is in the box?”

“Yes,” they agreed

“You just stated a hypothesis,” exclaimed Ms Clark

“A what?” asked Marcus

Figure 9 Investigations often begin by making observations and asking questions.

It's not very heavy.

What's that metal-like sound? It sounds like

a stapler.

Biologist Some ists study the livingworld, using mostly theirobservational skills Theyobserve animals andplants in their naturalenvironment, taking carenot to disturb the organ-isms they are studying.Make observations oforganisms in a nearbypark or backyard Recordyour observations in yourScience Journal

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