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GRADE 7

Florida Science

Introducing Science

Unifying Principles of Science Florida Student Handbook

FL26 FL30 FL36

The Nature of Science

1 Basic tools of science are universal.

2 5 13 14 22 24 31

CONNECTING SCIENCES The Science of Clean Water

2 Scientific ideas are based on evidence.

CHAPTER INVESTIGATION Using a Filter

3 Scientists belong to a world community.

MATH IN SCIENCE Making Bar Graphs

FLORIDA CONNECTIONS

Saving Coral Florida's Sinkholes Animatronics The Ultimate Fish

Sunshine State Standards

In "Saving Coral" you'll read how organisms called polyps grow, die, and decay, leaving skeletons that form coral reefs. (SC.D.1.3.2) Slight changes in a reef ecosystem can have long-term effects on population size. (SC.G.2.3.3)

42 190 334 450 564 666

A Place in the Sun Cape Canaveral: Step to the Stars

604 Unit 1: Earth's Waters

Student Resources

Florida Resources Florida Content Review/Preview FCAT Science Reference Appendix Student Resource Handbooks Scientific Thinking Handbook Lab Handbook Math Handbook Note-Taking Handbook Glossary Index Acknowledgments

809 811 823 825 R1 R2 R10 R36 R45 R52 R74 R117 FL7

UNIT 1

Earth's Waters

Unit Features

FRONTIERS IN SCIENCE Exploring the Water Planet FLORIDA CONNECTION Saving Coral TIMELINES IN SCIENCE Exploring the Ocean 38 42 146 46 49 55 56 63 64 72

The Water Planet

1 Water continually cycles.

Water moves through Earth's atmosphere, oceans, and land in a cycle.

THINK SCIENCE Does Mars Have a Water Cycle?

2 Fresh water flows and freezes on Earth.

MATH IN SCIENCE Multiplying Fractions and Whole Numbers

3 Fresh water flows underground.

CHAPTER INVESTIGATION Water Moving Underground

Freshwater Resources

1 Fresh water is an essential resource.

78 81 89 90 98 100 107

Fresh water is a limited resource and is essential for human society.

MATH IN SCIENCE Volume of Rectangular Prisms

2 Society depends on clean and safe water.

CHAPTER INVESTIGATION Monitoring Water Quality

3 Water shortages threaten society.

SCIENCE ON THE JOB Water and Farming

In what ways do you depend on water? page 78

FL8 McDougal Littell Science

What causes these waves? page 112

Ocean Systems

1 The oceans are a connected system.

112 115 123 124 129 134 136 141

The oceans are a connected system of water in motion.

MATH IN SCIENCE Plotting Coordinates

2 Ocean water moves in currents. 3 Waves move through oceans.

CHAPTER INVESTIGATION Wave Movement

4 Waters rise and fall in tides.

CONNECTING SCIENCES Tidal Energy

Ocean Environments

1 Ocean coasts support plant and animal life.

150 153 160 161 169 170 178

The ocean supports life and contains natural resources.

MATH IN SCIENCE Making a Double Bar Graph

2 Conditions differ away from shore.

EXTREME SCIENCE Undersea Hot Spots

3 The ocean contains natural resources.

CHAPTER INVESTIGATION Population Sampling

Ocean Waves

Waves transport energy, not water. As a wave crest passes, the water particles move in circular paths.

water particle movement wave direction

Visual Highlights

Springs and Wells Sources of Water Pollution The Ocean Floor Ocean Waves Intertidal Zone Coral Reefs Life in the Open Ocean

C

Waves affect only the water near the surface. The deeper water particles move in smaller circles than the water particles near the surface. Below a certain depth, waves no longer affect the water.

The movement of the floating inner tube is similar to the movement of the water particles.

Water particles rise as a wave crest approaches.

Wave Structure

Wavelength is the distance between one wave crest and the next.

At the crest, water particles have moved in a semicircle.

Wave height is the vertical distance between the top of the crest and the bottom of the trough.

The crest is the high point of the wave.

Water particles drop after the trough passes.

The trough is the low point of the wave.

The wave passes through the water but the water particles end up in the same place they began.

69 95 120 131 155 163 167

What happens to water particles as a wave passes through?

Chapter 3: Ocean Systems 91

Table of Contents FL9

UNIT 2

Earth's Surface

Unit Features

FRONTIERS IN SCIENCE Remote Sensing FLORIDA CONNECTION Florida's Sinkholes TIMELINES IN SCIENCE History of the Earth System 186 190 292

Views of Earth Today

1 Technology is used to explore the Earth system.

194 197 203 211 212 216 218 223

Modern technology has changed the way we view and map Earth.

2 Maps and globes are models of Earth.

MATH IN SCIENCE Using Proportions

3 Topographic maps show the shape of the land.

CHAPTER INVESTIGATION Investigate Topographic Maps

4 Technology is used to map Earth.

THINK SCIENCE Which Site Is Best for an Olympic Stadium?

Weathering and Soil Formation

1 Mechanical and chemical forces break down rocks.

228 231 237 238 246 248 253

Natural forces break rocks apart and form soil, which supports life.

MATH IN SCIENCE Surface Area of a Prism

2 Weathering and organic processes form soil.

CHAPTER INVESTIGATION Testing Soil

3 Human activities affect soil.

SCIENCE ON THE JOB Soil, Water, and Architecture

How is rock related to soil? page 228

FL10 McDougal Littell Science Grade 7

Erosion and Deposition

1 Forces wear down and build up Earth's surface.

258 261 266 272 274 280 281 287

Water, wind, and ice shape Earth's surface.

2 Moving water shapes land.

CHAPTER INVESTIGATION Creating Stream Features

3 Waves and wind shape land.

CONNECTING SCIENCES Life on Dunes

4 Glaciers carve land and move sediments.

MATH IN SCIENCE Creating a Line Graph

Natural Resources

1 Natural resources support human activity.

296 299 307 308 312 313 322

Society depends on natural resources for energy and materials.

CONNECTING SCIENCES Got Oil Spills?

2 Resources can be conserved and recycled.

MATH IN SCIENCE Comparing Decimals

3 Energy comes from other natural resources.

CHAPTER INVESTIGATION Wind Power

How do people obtain energy from Earth's resources? page 296

Visual Highlights

Mechanical Weathering World Soil Types Organisms and Soil Formation Types of Glaciers and Movement Natural Resources

233 241 243 283 301

Table of Contents FL11

UNIT 3

Electricity and Magnetism

Unit Features

FRONTIERS IN SCIENCE Electronics in Music FLORIDA CONNECTION Animatronics TIMELINES IN SCIENCE The Story of Electronics 330 334 404

Electricity

1 Materials can become electrically charged.

338 341 349 350 358 360 367

Moving electric charges transfer energy.

CONNECTING SCIENCES Electric Eels

2 Charges can move from one place to another.

CHAPTER INVESTIGATION Lightning

3 Electric current is a flow of charge.

MATH IN SCIENCE Using Variables

Circuits and Electronics

1 Charge needs a continuous path to flow.

372 375 382 383 388 389 398

Circuits control the flow of electric charge.

SCIENCE ON THE JOB The Science of Electrical Work

2 Circuits make electric current useful.

MATH IN SCIENCE Solving Percent Problems

3 Electronic technology is based on circuits.

CHAPTER INVESTIGATION Design an Electronic Communication Device

How can circuits control the flow of charge? page 372

FL12 McDougal Littell Science Grade 7

What force is acting on this compass needle? page 408

Magnetism

1 Magnetism is a force that acts at a distance.

408 411 419 420 427 432 434 439

Current can produce magnetism, and magnetism can produce current.

THINK SCIENCE Can Magnets Heal People?

2 Current can produce magnetism. 3 Magnetism can produce current.

CHAPTER INVESTIGATION Build a Speaker

4 Generators supply electrical energy.

MATH IN SCIENCE Using Significant Figures

Visual Highlights

How a Photocopier Works How Lightning Forms Batteries How a PC Works How Magnets Differ from Other Materials How a Motor Works

347 353 365 394 415 425

Table of Contents FL13

UNIT 4

Life Over Time

Unit Features

FRONTIERS IN SCIENCE Life by Degrees FLORIDA CONNECTION The Ultimate Fish TIMELINES IN SCIENCE Life Unearthed 446 450 520

Views of Earth's Past

1 Earth's past is revealed in rocks and fossils.

454 457 464 465 472 473 480

Rocks, fossils, and other types of natural evidence tell Earth's story.

CONNECTING SCIENCES Could T. Rex Win a Race?

2 Rocks provide a timeline for Earth.

MATH IN SCIENCE Interpreting Graphs

3 The geologic time scale shows Earth's past.

CHAPTER INVESTIGATION Geologic Time

What does this footprint tell you about the animal that left it? page 454

FL14 McDougal Littell Science Grade 7

How do scientists learn about the history of life on Earth? page 486

The History of Life on Earth

1 Earth has been home to living things for about

486

Living things, like Earth itself, change over time.

3.8 billion years.

MATH IN SCIENCE Using Proportions

2 Species change over time.

489 496 497 506

CHAPTER INVESTIGATION Modeling Natural Selection

3 Many types of evidence support evolution.

508 THINK SCIENCE How Did the Deep-Sea Angler Get Its Glow? 515

Population Dynamics

1 Populations have many characteristics.

524 527 535 536 543 544 552

Populations are shaped by interactions between organisms and the environment.

MATH IN SCIENCE Finding Averages

2 Populations respond to pressures.

SCIENCE ON THE JOB Studying the Schools

3 Human populations have unique responses to change.

CHAPTER INVESTIGATION Sustainable Resource Management

Visual Highlights

Fossils in Rocks Radioactive Breakdown Natural Selection Biological Evidence for Evolution

461 470 503 511

Table of Contents FL15

UNIT 5

Human Biology

Unit Features

FRONTIERS IN SCIENCE Surprising Senses FLORIDA CONNECTION A Place in the Sun TIMELINES IN SCIENCE Seeing Inside the Body 560 564 624

Systems, Support, and Movement

1 The human body is complex.

568 571 575 576 583 584 590

The human body is made up of systems that work together to perform necessary functions.

THINK SCIENCE What Does the Body Need to Survive?

2 The skeletal system provides support and protection.

MATH IN SCIENCE Comparing Rates

3 The muscular system makes movement possible.

CHAPTER INVESTIGATION A Closer Look at Muscles

What materials does your body need to function properly? page 596

FL16 McDougal Littell Science Grade 7

Red blood cells travel through a blood vessel. How do you think blood carries materials around your body? page 628

Absorption, Digestion, and Exchange 596

1 The respiratory system gets oxygen and removes

Systems in the body obtain and process materials and remove waste.

carbon dioxide.

SCIENCE ON THE JOB Breathing and Yoga

2 The digestive system breaks down food.

599 606 607 613 614 618

MATH IN SCIENCE Choosing Units of Length

3 The urinary system removes waste materials.

CHAPTER INVESTIGATION Modeling a Kidney

Transport and Protection

1 The circulatory system transports materials.

628 631 638 640 648 649 655

Systems function to transport materials and to defend and protect the body.

CHAPTER INVESTIGATION Heart Rate and Exercise

2 The immune system defends the body.

MATH IN SCIENCE Making a Line Graph

3 The integumentary system shields the body.

EXTREME SCIENCE Artificial Skin

The Skeletal System

The skeletal system interacts with other body systems to allow this soccer player to stand, run, and kick.

Axial skeleton Appendicular skeleton The skull protects the brain. The lower jaw is the only bone in the skull that can move.

Visual Highlights

The shoulder blade is called the scapula. The upper arm bone is called the humerus. The lower arm bones are the ulna and radius.

Twelve pairs of ribs protect the lungs and heart.

The vertebrae of the spinal column protect the spinal cord and support the cranium and other bones.

The many bones in the wrist and the hand allow it to perform a great variety of activities. The upper leg bone, called the femur, is the longest bone in the body. The kneecap is called the patella.

The Skeletal System Muscle Tissue Respiratory System Digestive System Circulatory System

579 587 603 611 634

The lower leg bones are called the tibia and the fibula.

There are 26 bones in the ankle and the foot.

The word appendicular has the same root as the word append, which means to attach. How do you think this word applies to the appendicular skeleton?

Chapter 1: Systems, Support, and Movement 17

Table of Contents FL17

UNIT 6

Space Science

Unit Features

FRONTIERS IN SCIENCE Danger from the Sky FLORIDA CONNECTION Cape Canaveral: Step to the Stars TIMELINES IN SCIENCE The Story of Astronomy 662 666 736

Exploring Space

1 Some space objects are visible to the human eye.

670 673 679 684 686 694 695 699

People develop and use technology to explore and study space.

2 Telescopes allow us to study space from Earth.

CHAPTER INVESTIGATION Observing Spectra

3 Spacecraft help us explore beyond Earth.

MATH IN SCIENCE Using Exponents

4 Space exploration benefits society.

CONNECTING SCIENCES How Earth's Gravity Affects Plants

Earth, Moon, and Sun

1 Earth rotates on a tilted axis and orbits the Sun.

704 707 714 716 722 723 731

Earth and the Moon move in predictable ways as they orbit the Sun.

CHAPTER INVESTIGATION Modeling Seasons

2 The Moon is Earth's natural satellite.

MATH IN SCIENCE Making Line Graphs

3 Positions of the Sun and Moon affect Earth.

SCIENCE ON THE JOB Astronomy in Archaeology

What would you see if you looked at the Moon with a telescope? page 704

FL18 McDougal Littell Science Grade 7

This image shows Jupiter with one of its large moons. How big are these objects compared with Earth? page 740

Our Solar System

1 Planets orbit the Sun at different distances.

740 743 748 749 757 758 764 770

Planets and other objects form a system around our Sun.

MATH IN SCIENCE Using Percentages

2 The inner solar system has rocky planets.

THINK SCIENCE What Shapes the Surface of Mars?

3 The outer solar system has four giant planets. 4 Small objects are made of ice and rock.

CHAPTER INVESTIGATION Exploring Impact Craters

Stars, Galaxies, and the Universe

1 The Sun is our local star.

776 779 784 786 793 794 798 799

Our Sun is one of billions of stars in one of billions of galaxies in the universe.

CHAPTER INVESTIGATION Temperature, Brightness, and Color

2 Stars change over their life cycles.

MATH IN SCIENCE Interpreting a Scatter Plot

3 Galaxies have different sizes and shapes.

EXTREME SCIENCE When Galaxies Collide

4 The universe is expanding.

Visual Highlights

Structures in the Universe Seasons Lunar Phases Objects in the Solar System Features of Rocky Planets Layers of the Sun Life Cycles of Stars

675 711 725 744 751 781 791 Table of Contents FL19

Features

SKILL: VOLUME OF RECTANGULAR PRISMS

Fish in an Aquarium

MATH TUTORIAL

CLASSZONE.COM

SPACE SCIENCE

A fish requires a certain minimum amount of water to survive. If you plan to keep fish in an aquarium, you can calculate the volume of the aquarium to be sure it will contain enough water.

Click on Math Tutorial for more help finding the volume of a rectangular prism.

Example

An aquarium is 50 centimeters long, 30 centimeters wide, and 40 centimeters high. 40 cm How many liters of water will it hold?

Solution

Volume = length V = lwh = 50 cm width height

50 cm

30 cm

Use the formula for the volume of a rectangular prism.

30 cm

40 cm

Write a word equation. Replace the words with variables. Substitute 50 for l, 30 for w, and 40 for h.

Using Exponents Making Line Graphs Using Percentages Interpreting a Scatter Plot

694 722 748 793

Multiply. Note that cm3 is a cubic centimeter. Each cubic centimeter holds a milliliter. = 60 L Because there are 1000 milliliters in one liter, divide 60,000 by 1000. ANSWER The aquarium holds 60 liters of water. = 60,000 mL

= 60,000 cm3

Find the volume of each aquarium. Give your answer in liters.

Think Science

EARTH'S WATERS

1. The aquarium is 100 centimeters long, 50 centimeters wide, and 80 centimeters high. 2. The aquarium is 50 centimeters long, 20 centimeters wide, and 40 centimeters high. 3. The aquarium is 50 centimeters long, 40 centimeters wide, and 50 centimeters high. CHALLENGE You are designing an aquarium to house several fish of different species. The aquarium must hold 300 liters of water and fit in a space that is 100 centimeters long and 50 centimeters wide. How high should the aquarium be?

Determining Relevance

EARTH'S SURFACE

55 223 419 515 575 757

Chapter 3: Freshwater Resources 89

Interpreting Data

Math in Science

NATURE OF SCIENCE

ELECTRICITY AND MAGNETISM

Evaluating Conclusions

LIFE OVER TIME 31

Making Bar Graphs

EARTH'S WATERS

Evaluating Hypotheses

HUMAN BIOLOGY

Multiplying Fractions and Whole Numbers 63 Volume of Rectangular Prisms 89 Plotting Coordinates 123 Making a Double Bar Graph 160

EARTH'S SURFACE

Inferring

SPACE SCIENCE

Forming Hypotheses

Using Proportions Surface Area of a Prism Creating a Line Graph Comparing Decimals

ELECTRICITY AND MAGNETISM

211 237 287 312 367 388 439 472 496 535 583 613 648

Connecting Sciences

NATURE OF SCIENCE

Physical Science and Earth Science

EARTH'S WATERS

13 141 208 307 349 464 699

Using Variables Solving Percent Problems Using Significant Figures

LIFE OVER TIME

Earth Science and Physical Science

EARTH'S SURFACE

Earth Science and Life Science Earth Science and Life Science

ELECTRICITY AND MAGNETISM

Interpreting Graphs Using Proportions Finding Averages

HUMAN BIOLOGY

Physical Science and Life Science

LIFE OVER TIME

Comparing Rates Choosing Units of Length Making a Line Graph

Earth Science and Life Science

SPACE SCIENCE

Earth Science and Life Science

FL20 McDougal Littell Science Grade 7

EARTH'S SURFACE

LANDSCAPE ARCHITECT

Remote Sensing

ELECTRICITY AND MAGNETISM

186 330 446 560 662

Soil, Water, and Architecture

Existing Plants

Large oak trees were already growing on the land. The trees were left in place to provide shade and help protect the soil.

Landscape architects design the landscapes around buildings and in parks. For example, they decide where to build sidewalks and where to place benches. Since flowing water can wash away soil, they try to control how water moves. They select plants, modify the slope of the land, and install drainage systems that will control the water. The plan below was used to build the park shown in the photographs.

Electronics in Music

LIFE OVER TIME

Life by Degrees

Retaining Wall

The landscape architect added mounds of soil planted with bushes to help divide the inside of the park from the roads around it. Stone walls hold the soil of the mounds in place. Without the walls, the soil would wash down onto the walkways.

HUMAN BIOLOGY

Surprising Senses

SPACE SCIENCE

Plan for New Park

A landscape architect used a computer program to draw this plan for a park. The program is designed to make the plan look as if it were drawn by hand.

EXPLORE

1. ANALYZE Examine the soil, drainage, plants, and other elements of the landscape of a park or the area around a building. Describe any areas where soil may wash away. 2. CHALLENGE Design a landscape surrounding a new school, stadium, or other building. Draw a sketch and add notes to explain your choices of locations for trees, sidewalks, and other features.

Danger from the Sky

Chapter 7: Weathering and Soil Formation 253

Florida Connections

EARTH'S WATERS

Science on the Job

EARTH'S WATERS

Saving Coral

EARTH'S SURFACE 107 253 382 543 606 731

42 190 334 450 564 666

Water and Farming

EARTH'S SURFACE

Florida's Sinkholes

ELECTRICITY AND MAGNETISM

Soil, Water, and Architecture

ELECTRICITY AND MAGNETISM

Animatronics

LIFE OVER TIME

The Science of Electrical Work

LIFE OVER TIME

The Ultimate Fish

HUMAN BIOLOGY

Studying the Schools

HUMAN BIOLOGY

A Place in the Sun

SPACE SCIENCE

Breathing and Yoga

SPACE SCIENCE

Cape Canaveral: Step to the Stars

Astronomy in Archaeology

Timelines in Science

EARTH'S WATERS

Extreme Science

EARTH'S WATERS

Exploring the Ocean

EARTH'S SURFACE 169 655 798

146 292 404 520 624 736

Undersea Hot Spots

HUMAN BIOLOGY

History of the Earth System

ELECTRICITY AND MAGNETISM

Artificial Skin

SPACE SCIENCE

The Story of Electronics

LIFE OVER TIME

When Galaxies Collide

Life Unearthed

HUMAN BIOLOGY

Frontiers in Science

EARTH'S WATERS

Seeing Inside the Body

SPACE SCIENCE

Exploring the Water Planet

The Story of Astronomy

38

Table of Contents FL21

Internet Resources @ ClassZone.com

ClassZone.com

Back Forward Reload Home Images Print Security Stop

Visualizations

EARTH'S WATERS

Location:

http://www.classzone.com

The Water Cycle Water Treatment Plant Daily Tides Life at Hydrothermal Vents

EARTH'S SURFACE

53 92 137 168 206 229 234 259 270 320 395 424 467 490 534 597 608 629 653 676 705 724 741 777

Latitude and Longitude Soil Formation Chemical Weathering Wind Erosion Cave Formation Hydrogen Fuel Cell

ELECTRICITY AND MAGNETISM

Simulations

EARTH'S WATERS

Hard Drive Motor

LIFE OVER TIME 66 79 113 151 215 315 339 361 373 409 487 569 578 671 780

Aquifers Limits of an Aquifer The Ocean Floor Ocean Life and Environments

EARTH'S SURFACE

Molten Rock in Sedimentary Layers Fossil Formation Response to Environmental Change

HUMAN BIOLOGY

Topographic Maps and Surface Features Nuclear Power Plant

ELECTRICITY AND MAGNETISM

Lung and Diaphragm Movement Peristalsis Heart Pumping Blood Skin Healing

SPACE SCIENCE

Static Electricity Ohm's Law Circuits Electromagnets

LIFE OVER TIME

Night Sky throughout the Year Exploring Seasons Lunar Phases Virtual Flight through the Solar System Shapes of Galaxies

Matching Finch Beaks to Food

HUMAN BIOLOGY

Human Body Systems Assemble a Skeleton

SPACE SCIENCE

Career Centers

Oceanography Mineralogy Music and Computer Science Paleontology Neurobiology Astronomy

41 189 333 449 563 665

Levels of the Universe Sun at Different Wavelengths

FL22 McDougal Littell Science Grade 7

Resource Centers

NATURE OF SCIENCE

Math Tutorials

NATURE OF SCIENCE

Resources for the following topics may be found at ClassZone.com: Ethics; Prions; Technology and Its Consequences; Aquifers and Purification.

EARTH'S WATERS

Bar Graphs

EARTH'S WATERS

31

Resources for the following topics may be found at ClassZone.com: Florida's Coral Reefs; Water; Evidence of a Water Cycle on Mars; Frozen Fresh Water; Geysers and Hot Springs; Ocean Currents; Ocean Waves; Ocean Tides; Ocean Research; Coral Reefs; Hydrothermal Vents; Ocean Pollution and Pollution Prevention.

EARTH'S SURFACE

Multiplying Fractions and Whole Numbers 63 Volume of a Rectangular Prism 89 Coordinates and Line Graphs 123 Bar Graphs 160

EARTH'S SURFACE

Solving Proportions Surface Area of a Rectangular Prism Making a Line Graph Comparing Decimals

ELECTRICITY AND MAGNETISM

211 237 287 312 367 388 439

Resources for the following topics may be found at ClassZone.com: Sinkholes; Satellite Mapping; Map Projections; GIS; Weathering; Soil; Mudflows; Rivers and Erosion; Glaciers; Earth System Research; Natural Resources; Pollution-Digesting Microbes; Renewable Energy Resources.

ELECTRICITY AND MAGNETISM

Equations Percents and Proportions Rounding Decimals

LIFE OVER TIME

Reading Line Graphs and Multiplying Whole Numbers Writing and Solving Proportions Finding the Mean

HUMAN BIOLOGY

472 496 535 583 613 648 694 722 748 793

Resources for the following topics may be found at ClassZone.com: Amusement Park Animatronics; Lightning and Lightning Safety; Electrochemical Cells; Electrical Safety; Electronics; Electronic and Computer Research; Magnetism; Dams and Electricity; Energy Use and Conservation.

LIFE OVER TIME

Unit Rates Measuring Length Making Line Graphs

SPACE SCIENCE

Resources for the following topics may be found at ClassZone.com: Sharks; Evidence of an Event in Earth's Past; Fossils; Finding the Ages of Rocks; Mass Extinctions; Natural Selection; Evidence Supporting Evolution; Current Fossil and Living Fossil Finds; Population Dynamics; Human Population Growth; Introduced Species in the United States.

HUMAN BIOLOGY

Powers and Exponents Line Graphs The Percent Equations Scatter Plots

NSTA SciLinks

Codes for use with the NSTA SciLinks site may be found on every chapter opener.

Resources for the following topics may be found at ClassZone.com: Skin and the Sun; Shackleton's Expedition; Skeletal System; Muscles; Respiratory System; Urinary System; Current Medical Imaging Techniques; Circulatory System; Blood Types; Lymphatic System; Skin.

SPACE SCIENCE

Florida Review

There is a content review and FCAT practice for every chapter at ClassZone.com.

Resources for the following topics may be found at ClassZone.com: Cape Canaveral; Telescopes; Space Exploration; Seasons; Tides; Advances in Astronomy; Impact Craters; Moons of Giant Planets; Life Cycles of Stars; Galaxies; Galaxy Collisions.

Table of Contents FL23

Explore the Big Idea

Chapter Opening Inquiry Each chapter opens with hands-on explorations that introduce the chapter's Big Idea.

The Nature of Science

All sciences use similar processes and tools. Growers sometimes spray water on oranges in cold weather. How did they figure out that this would help protect the fruit?

Reproducing a Result

Using only a cup of water and a ping-pong ball, find a way to make the ball float so that it does not touch the cup. Write down your procedure. Observe and Think Why is it important to keep detailed records of a procedure?

Key Concepts

SECTION

Effects of Changes

Use a plastic straw, paper strips, and tape to make a glider like the one shown in the photograph. Hold the glider with the smaller loop of paper in front. Throw the glider several times and measure how far it flies. Then, change the size of the loops or use different shapes of paper. Test the glider's flight after each change. Observe and Think How did each change affect the flight of your glider?

1

Basic tools of science are universal.

Learn why different sciences share a common approach.

SECTION

2

Scientific ideas are based on evidence.

Learn how different kinds of scientific inquiries are used to gather evidence.

SECTION

3

Scientists belong to a world community.

Learn how science and society interact with one another.

Internet Activity: Ethics

Go to ClassZone.com to learn more about ethics and scientific study. Observe and Think What are some of the ethical questions scientists face? Is there always one right answer to an ethical question?

ClassZone.com

Back Forward Reload Home Images Print Security Stop

Location:

http://www.classzone.com

· Section Reviews, pp. 14, 25, 33, 38 · Chapter Review, pp. 34-36 · FCAT Practice, p. 37 CLASSZONE.COM · Florida Review: Content Review and FCAT Practice

NSTA

scilinks.org

Solutions Code: MDL069

2 Chapter 1: The Nature of Science

Chapter 1: The Nature of Science 3

Nature of Science Reproducing a Result; Effects of Changes Earth's Waters Where Can You See Water? Does the Ice Float? How Much Water Do You Drink? What Happens When Salt Water Evaporates? What Makes Things Float or Sink? How Does Moving Air Affect Water? It's Alive! Beneath the Surface Earth's Surface Earth's Changing Surface; Using Modern Maps Ice Power; Getting the Dirt on Soil Where Has Water Been? How Do Waves Shape Land? Sunlight as an Energy Source; Saving Water as You Brush Electricity and Magnetism How Do the Pieces of Tape Interact? Why Does the Water React Differently? Will the Flashlight Still Work? What's Inside a Calculator? Is It Magnetic? How Can You Make a Chain?

3

47 79 113 151

Life Over Time How Do You Know What Happened? How Long Has That Been There? What Can Rocks Show About Earth's History? Which One of These Things Is Not Like the Others? How Does Population Grow? How Do Populations Differ? Human Biology How Many Bones Are in Your Hand? How Does It Move? Mirror, Mirror; Water Everywhere Blood Pressure; Wet Fingers Space Science Why Does the Sun Appear to Move Around Earth? What Colors Are in Sunlight? How Do Shadows Move? What Makes the Moon Bright? How Big Is Jupiter? How Round Is an Orbit? How Can Stars Differ? How Do Galaxies Move Apart?

455

487 525

569 597 629

195 229 259 297

671 705 741 777

339 373 409

FL24 McDougal Littell Science Grade 7

CHAPTER INVESTIGATION

Chapter Investigations

Full-Period Labs The Chapter Investigations are in-depth labs that let you form and test a hypothesis, build a model, or sometimes design your own investigation.

MATERIALS

· clean water · contaminants such as: soil, vinegar, vegetable oil, food coloring, dry leaves · 1 L container · stirrers · 8 clear cups · 50 mL beaker · masking tape and marker · 2 funnels · coffee filters · rubber bands · pieces of cloth · coarse sand · charcoal · stopwatch Challenge Materials · alum · 2 clear cups

Using a Filter

OVERVIEW AND PURPOSE Using variables in a

controlled experiment can help you determine many things. For example, the effectiveness of a filter to clean water depends on the type of filter that is used and the condition of the water. By testing different filters and gathering evidence you can determine which filter is the most effective. Keep in mind that that the independent variable is the factor that you wish to test and the dependent variable is what you measure to determine your results. In this investigation you will · make water dirty and try to clean it · identify the variables

Write

It Up

Measure 30 mL of clean water. Pour the water into one of the cups. Use the marker to mark the level on the masking tape. Repeat so that all of the cups are marked at 30 mL. Label your cups A­F. Pour 100 mL of clean water into one of your filters. Discard the filtered water. Pour 50 mL of clean water into one of the filters so that it empties into cup A. Record the time it takes for 30 mL to run through the filter. Observe the water and filter. Repeat step 5 two times using dirty water.

Conclude

Write

It Up

1. COMPARE Which filter was the most

effective? Present your evidence. How did the filters differ in terms of the two dependent variables?

2. EVALUATE Were the trials of each filter

consistent? If not, explain what changed.

3. APPLY Suppose you want to design a filter

to clean the water in a fish tank. How would this filter differ from the ones that you tested?

Problem

Which filter is the most effective?

INVESTIGATE Further

CHALLENGE Particles settle to the bottom of liquids over time. Alum is a material that binds very small particles together in a liquid and helps them settle. Add 1 mL of alum to 50 mL of dirty water. Set up a control sample with no alum. Stir the samples and then observe them after 10­15 minutes. How could alum help your filtering experiment?

Procedure

Work with a partner. Decide which contaminants to add to your clean water. Measure and record the amount of each ingredient that you use. Mix your water thoroughly in a large container. You should make at least 1 L of dirty water. Choose two of the following filters and set them up. · filter paper Line your funnel with a coffee filter. · cloth Line a funnel with a piece of cloth. · sand Use a rubber band to secure a piece of cloth around the bottom of the funnel, which will hold the sand. Choose and measure an amount of sand and pour it into the funnel. · charcoal Follow the procedure for sand except use charcoal. · other Combine any of the materials and ideas listed above to design your own filter. Record what you use to make the filter.

Repeat steps 4­6 using your second filter and cups D­F.

Observe and Analyze

Write

It Up

1. RECORD Make sure you have recorded all

the measurements and observations in your science notebook.

2. OBSERVE Which filter removed the most

impurities? What characteristics are you using to describe the water? Through which filter did water flow faster?

3. INTERPRET What was the purpose of

pouring clean water through the filters in step 5?

Using A Filter Observe and Analyze Test Results Table 1. Filtering

Cup Filter Material Control Trial 1 Trial 2 Control Trial 1 Trial 2 Time (sec) (A) (B) (C) (E) (F) (G)

Observations

4. IDENTIFY VARIABLES List the

independent variable and the two dependent variables.

22 Chapter 1: The Nature of Science

Chapter 1: The Nature of Science 23

Nature of Science Using a Filter Earth's Waters Water Moving Underground Monitoring Water Quality Wave Movement Population Sampling

22

Life Over Time Geologic Time Modeling Natural Selection Sustainable Resource Management Human Biology A Closer Look at Muscles Modeling a Kidney Heart Rate and Exercise Space Science Observing Spectra Modeling Seasons Exploring Impact Craters Design Your Own Temperature, Brightness, and Color

480 506 552

Design Your Own

72 98 134 178

Earth's Surface Investigate Topographic Maps Testing Soil Creating Stream Features Wind Power

590 618 638

216 246 272 322

Electricity and Magnetism Lightning 358 Design an Electronic Communication Device Design Your Own 398 Build a Speaker 432

684 714 770 784

Table of Contents FL25

KEY CONCEPT

Explore

Introductory Inquiry Activities Most sections begin with a simple activity that lets you explore the Key Concept before you read the section.

Basic tools of science are universal.

Sunshine State STANDARDS

SC.H.1.3.2: The student knows that the study of the events that led scientists to discoveries can provide information about the inquiry process and its effects. SC.H.1.3.3: The student knows that science disciplines differ from one another in topic, techniques, and outcomes, but that they share a common purpose, philosophy, and enterprise. SC.H.1.3.6: The student recognizes the scientific contributions that are made by individuals of diverse backgrounds, interests, talents, and motivations.

BEFORE, you learned

· Science collect evidence by making observations. · Scientific results must be reproducible. · Scientists record and share results.

NOW, you will learn

· How people use scientific processes · About scientific habits of mind · How scientists build up scientific information

EXPLORE Observations and Opinions

How are observations different from opinions?

PROCEDURE

1

MATERIALS

· 3 bottles with lids · water · spoon · 3 types of cleaning products

Fill the bottles one-third full with water. cleaning product to each bottle. Fasten the lids tightly and shake each bottle for 15 seconds.

2 Add one spoonful of a different type of

3 Observe the suds in each bottle.

WHAT DO YOU THINK?

VOCABULARY

scientific processes p. 4 hypothesis p. 5 creative thinking p. 6 skepticism p. 7 critical thinking p. 8

How is comparing the height of suds produced by each cleaning product different from comparing how good they smell?

Science is a way to study the natural world.

People continually ask questions, explore ideas, and reach conclusions. Sometimes scientific methods can help them, but not all questions can be answered scientifically. For example, suppose people are deciding which musicians to invite to perform in the town's park. They might discuss their opinions vigorously, but science cannot help them make the best choice. What can be studied scientifically? Anything that can be observed objectively and involves features of the natural world. Objective observations are the same for everyone. For example, choosing the best type of grass to plant in the park can be approached scientifically. People can test varieties of grass to find out which would grow well in the park and withstand being walked on by large numbers of concert-goers. The grasses are part of the natural world, their growth can be tested, and different observers will get similar results.

Chapter 1: The Nature of Science 5

Nature of Science Observations and Opinions Effects of Changes in Procedures Earth's Waters Water Vapor Water Collection Flow of Water Concentration The Value of Fresh Water Density Currents Waves Air Bladders Ocean Pollution Earth's Surface Mapping Topographic Maps Mechanical Weathering Soil Composition Divides Glaciers Energy Use Nuclear Energy Electricity and Magnetism Static Electricity Static Discharge Current Circuits Codes Magnetism Magnetism from Electric Current Energy Conversion

5 14

49 56 64 90 100 115 124 129 161 170

Life Over Time Rocks Time Scales Fossils Evidence Population Density Population Change Human Biology Levers Muscles Breathing Digestion Waste Removal The Circulatory System Membranes The Skin Space Science Distance Distortion of Light Viewing Space Objects Time Zones The Moon's Motion Planet Formation Surfaces Solar Atmosphere Characteristics of Stars The Milky Way Large Numbers

457 473 489 508 536 544

576 584 599 607 614 631 640 649

203 212 231 238 266 281 308 313

341 350 360 375 389 411 420 427

673 679 686 707 716 743 749 779 786 794 799

FL26 McDougal Littell Science Grade 7

Water moves in a worldwide cycle.

Investigate

Skill Labs Each Investigate activity gives you a chance to practice a specific science skill related to the content that you're studying.

MAIN IDEA AND DETAILS

Record in your notes this main idea and important details about the water cycle.

Water continually moves and changes form. Water from clouds falls over the oceans and on land. Water flows in rivers and collects in lakes and under the ground. Water can be a solid in the form of ice, or it can be an invisible vapor in the atmosphere.

The Water Cycle Water's movement on Earth is a cycle, or continually repeating process. The water cycle is the continuous movement of water through the environment of Earth. In the water cycle, water is constantly changing form, from a liquid on land, to a vapor in the atmosphere, and again to a liquid that falls to the surface. The flow of water on land and underground is also part of the water cycle. As water moves in the water cycle, the total amount of water in Earth's system does not change very much. The water cycle involves three major processes: evaporation, condensation, and precipitation.

The Water Cycle

How does water cycle through an environment?

PROCEDURE

water, and containers.

2 Find the mass of your closed jar after you construct it. 3 Draw a detailed, colored picture of your jar. 4 Let your jar sit for several days.

template Use the guided m at www.publisher.co

SKILL FOCUS

Modeling

1 Construct an environment in a jar with a lid. You can use plants, soil,

I-Ahead

MATERIALS

· jar with lid · soil · rocks or pebbles · sand · smaller containers · water · small plants · triple-beam balance

5 Find the mass of your jar again, and draw another picture of it.

WHAT DO YOU THINK?

· How did the jar's appearance change over several days? · How did its mass change? · What can you conclude about how water cycles through an environment?

TIME

30 minutes (for construction; 20 minutes for analysis)

CHALLENGE How could you

change your environment so that the jar's appearance would change at a faster rate?

52 Unit 1: Earth's Waters

Nature of Science Solving Problems Ethics Earth's Waters The Water Cycle Icebergs Aquifer Filtration Water Usage Water Conservation Density Currents Tides Coastal Environments Floating Earth's Surface Geosphere's Layers Map Projections Satellite Imaging Chemical Weathering Soil Conservation Erosion Longshore Drift Kettle Lake Formation Fossil Fuels Conservation

Design Your Own Judging

9 28

Digital Information Earth's Magnetic Field Electromagnets Electric Current Power

Making Models Inferring Observing Inferring Making Models

391 417 422 430 437

Design Your Own Calculating Making Models Analyzing Data Measuring Predicting Observing Making Models Design Your Own Design Your Own

52 61 67 83 103 118 127 138 156 165

Life Over Time Learning from Tree Rings Relative and Absolute Age Fossil Records Genes Limiting Factors Population Human Biology Systems Movable Joints Lungs Chemical Digestion Antibodies Skin Protection Space Science Constellation Positions Launch Planning Weathering Rotation Moon Features Phases of the Moon Distances Layers Giant Planets Parallax Galaxy Shapes Galaxies

Observing Making Models Analyzing Sequencing Design Your Own Graphing data

462 468 491 513 540 548

Predicting Observing Making models Making models Making models Observing

Modeling Modeling Modeling Identifying Variables Making Models Design Your Own Observing Design Your Own Modeling Design Your Own

201 208 220 234 251 262 276 285 305 310

572 581 601 609 645 651

Analyzing Identifying Variables Predicting Making Models Inferring Making Models Using Models Using Models Observing Measuring Classifying Measuring

Electricity and Magnetism Making a Static Detector Inferring Conductors and Insulators Interpreting Data Electric Cells Inferring Fuses Making Models Circuits Inferring

346 354 363 380 386

677 689 697 708 719 726 746 752 761 787 795 802

Table of Contents FL27

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