Table of Contents South Carolina - Walch Correlations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TG21 ... Table of Contents South

Teacher’s GuideIntroduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TG1Teacher-to-Teacher Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TG4Pacing Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TG7

Grade 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TG7Grade 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TG11Grade 8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TG16

Standards Correlations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TG21Grade 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TG21Grade 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TG22Grade 8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TG24

Materials Lists . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TG27Grade 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TG27Grade 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TG29Grade 8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TG30

Graphic Organizers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TG33Best Practices for Science Instruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TG57

Grade 6 Motion, Forces, and Energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Kinematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1Dynamics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20Gravity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43Mechanical Energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62Temperature and Heat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

Waves, Light, Electricity, and Magnetism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109Sound Waves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109The Nature of Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133The Behavior of Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148The Basis of Electricity and Magnetism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169Applications of Electricity and Magnetism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195Modern Physics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216

Answer Key . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235Pre- and Post-Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243Application Activities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267

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Grade 7Ecology

Ecosystems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 277Interactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 297Biomes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 317

ChemistryStates and Changes of Matter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 337The Structure of Matter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 356The Periodic Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 379Intermolecular Forces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 398Solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 424

Answer Key . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 449Pre- and Post-Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 457Application Activities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 477

Grade 8Earth Science . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 481

Warm-Ups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 481What Is Planet Earth? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 497Within the Crust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 509Beneath the Crust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 526Earth’s History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 541Earth Science Assessment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 548Activities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 550Answer Key . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 566Hands-On Activities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 570

Space Science . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 587Warm-Ups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 587The Cosmos . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 598The Solar System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 613Earth’s Moon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 626Observations from Spaceship Earth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 636Space Science Assessment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 644Activities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 646Answer Key . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 657Hands-On Activities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 660

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Introduction South Carolinaacademic support program

TEACHER’S GUIDE

The South Carolina Academic Support Program (ASP) for Middle School Science is a complete, turnkeysolution for improving educational performance. It was developed in partnership with the RichlandOne school district in Columbia, South Carolina. Topics are built around accessible core curriculumensuring that the ASP is useful for striving students and diverse classrooms.

This program recognizes that many struggling students aren’t reached by traditional “skill anddrill” or strict test-prep approaches.

The ASP includes components that review, instruct as needed, provide practice, and assessstudents’ skills. Instructional tools and strategies are embedded throughout. The scope and sequenceaddresses the needs of students who require additional support in topics included in the SouthCarolina Science Academic Standards and the National Science Education Standards.

This 3-ring binder with sections for sixth, seventh, and eighth grade includes:

• Many hours of lessons with reproducible activity sheets

• Daily warm-ups or openers—to begin a class or to make a transition

• Embedded assessment to inform instruction and document achievement

• Application activities to provide hands-on experience

• A collection of inquiry-based lab activities

• A supportive teacher’s guide that:

• describes the purpose of the materials and options for using the package

• provides pacing guide options

• references relevant South Carolina Science Academic Standards

• recommends an assortment of graphic organizers for instructional use

Purpose of MaterialsThe South Carolina Academic Support Program for Middle School Science is a flexible program that hasbeen organized to fit your students’ needs in evening or summer school.

Each day’s schedule includes activities beginning with direct instruction and guided practice, andmoving on to opportunities for developing and applying new skills and concepts in application andlab situations.

The program addresses four standards for South Carolina. These include:

• Standard 6-5: The student will demonstrate an understanding of the law of conservation ofenergy and the properties of energy and work. (Physical Science)

• Standard 7-4: The student will demonstrate an understanding of how organisms interact withand respond to the biotic and abiotic components of their environment. (Earth Science, LifeScience)

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• Standard 7-5: The student will demonstrate an understanding of the classifications andproperties of matter and the changes that matter undergoes. (Physical Science)

• Standard 8-3: The student will demonstrate an understanding of materials that determine thestructure of Earth and the processes that have altered this structure. (Earth Science)

• Standard 8-4: The student will demonstrate an understanding of the characteristics, structure,and predictable motions of celestial bodies. (Earth Science)

The Characteristics of Science: Habits of Mind, the Nature of Science, and Scientific Inquiry areinfused throughout.

Structure of the BinderThe ASP is provided for your convenience in a binder format. The materials are completelyreproducible, allowing you to make as few or as many copies as you need. If students lose an activitysheet, just make a new one. Tabs allow you to access the sections of the binder quickly and easily.There are tabs for each grade level—6th, 7th, and 8th—and tabs for sections dividing theinstructional materials by standard or concept.

The Teacher’s Guide is the first section. Written for you, this section helps you navigate thematerials with the pacing guide for your grade level, offers a number of graphic organizers andsuggested strategies for their use, and shows how the lessons in each grade level correlate to theSouth Carolina Science Academic Standards.

The next sections focus on content and knowledge of: Energy and Work for 6th grade; Ecology andChemistry for 7th grade; and Earth and Space for 8th grade. The units in the ASP can beimplemented as outlined in the pacing guides, yet the design is flexible so that you can mix andmatch sections and units as the needs of your students and your instructional style dictate.

Each grade level has a section containing a collection of Application Activities, referencedthroughout the pacing guide. These suggested activities provide students with additional hands-onand real-life experience.

The final section includes pre- and post-tests to be used with each instructional unit. The pre-testswill allow you to identify relative strengths and weaknesses in prior knowledge and conceptualunderstanding, and to plan instruction and differentiation accordingly. The post-tests will serve asdocumentation of improved achievement and learning.

TEACHER’S GUIDEIntroduction

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Structure of UnitsNearly all of the instructional units have some common features.

In each class session, you will present a topic. Some topics may be a review for students. Othertopics may be completely new to them. After some instruction, you will provide students withpractice activities to try. Students will have a chance to talk about how they completed their work.There are additional materials to use if you are confident that students are ready to extend theirlearning. If students need more practice or further explanation, you can provide them with that, too!

1. The Goal Statement

Each unit begins with a brief objective of what students should know, understand, or be able do atthe end of the unit.

2. Words to Know

Vocabulary terms are provided as background information for instruction or to review key conceptsthat are addressed in the unit.

3. Direct Instruction

This section is a guide for a teacher-led activity to review and/or instruct students on a specificconcept or topic (activities are 15 to 45 minutes in length). Instructional strategies include lecture,modeling, discussion, group facilitation, and more. The activities may include the use of one or moreof the graphic organizers found in the Teacher’s Guide. This section includes manyillustrations/diagrams that can be presented to students on the board, via an overhead projector, orin a photocopied handout. Each lesson includes diagrams and sample problems to be presented tothe class in this manner.

5. Student Activity Sheets

Each unit includes three or more lesson tasks and activities to support students’ achievement oflearning objectives. These sheets are written for the student. They can be used in any combination ofteacher-led instruction, cooperative learning, or independent application of knowledge.

6. Assessments

Each unit includes pre- and post-tests to inform instructional decisions and to document the extentto which students grasped the concepts and skills addressed during the unit.




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Teacher-to-Teacher IntroductionAs a science teacher with 16 years of experience, I have taught students with a wide variety of abilitylevels. I have taught everything from struggling general science students with special education needsin a general science class, to seniors in honors physics. Across the entire range of students, I’ve foundthat they generally perform better at all levels when they know the goals that they must reach to besuccessful. I developed this Academic Support Program (ASP) with a Pacing Guide to help you helpyour students understand the goals they need to reach. Your students are in a position in which theyneed to review a large amount of material in a relatively short amount of time. This ASP hascondensed within it the core concepts of Earth science, ecology, chemistry, and physics.

I envision a typical day consisting of some review time in which students are given the opportunityto recall information about the day’s topics that they already know or might be able to remember.After this introductory warm-up, there will usually be a component of direct instruction in which youcover the highlights of the material that will be used that day. There will be labs and hands-onactivities (although not every day) that will help reinforce some of the key concepts without requiringa large amount of expensive and complicated equipment. Review activities that help reinforce thematerial are available for every section, and will afford students the opportunity to determinewhether or not they understand the key concepts. There is generally more material available for asingle day than students will be able to do, so some of these materials are high-priority, while otherscan be utilized when there is extra time in class, or as extra material to help struggling students.

Here is a summary of the materials that are included in the ASP:

The Pacing Guide has suggestions for content that should be covered each day, and a review ofthose suggestions will help you plan what materials you think are best suited to the needs of yourstudents each day.

The Pre-Tests are quick tools that generally consist of 10 multiple-choice questions that will allowyou to do a quick survey of the topics that need to be covered in a given unit. This will also be a goodplace to ask students what they remember about the material you’ll be covering in that unit. If moststudents in your class seem to be familiar with a topic or concept, you can skip it or review lightlyduring instruction. If individual students seem to be missing something that others are familiar with,you can provide individual attention. If the whole class misses one or more of the questions, you’llknow that the planned instruction is right on target.

The Warm-Up is meant to be a 5-minute activity that asks students to consider a concept thatthey have probably been exposed to before, but may not remember in its entirety. This will givestudents an opportunity to recall information they have seen before. This will help you determine thetopics that students are well-prepared to discuss and which ones they struggle with.

Direct Instruction is a collection of core material that covers the key ideas from a major sciencearea. This is a simplified and somewhat abbreviated lesson that can serve as a guide for the materialsyou will want to cover each day. Some parts may need to be photocopied and shared with students,while other parts, such as charts and diagrams, might need to be shown on an overhead during yourinstruction or drawn on a board for students to view. The direct instruction has a lot of material and




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is designed to allow the teacher to pick and choose sections that seem to best fit the needs of thestudents. You might choose to photocopy and hand out sections of the direct instruction for“jigsawing.” Instead of you delivering all of the information verbally, on the board, or via an overheadprojector, groups of students can each get a part of the lesson, and then summarize and present whatthey have learned to other students.

In Real Life notes appear occasionally in the direct instruction. These are short narratives youcan share with students to help jog their memories about concepts and events they have seen outsideof class. They can they share their experiences with their classmates, and help all students connect tothe material.

Labs are designed to cover a variety of concepts without requiring a large amount of equipmentand to give students more hands-on opportunities.

Application Activities are short, hands-on labs that give students another way to connect to thematerial. They are meant to be shorter than a full lab and require very little in the way of lab equipment,while still covering important topics. Application Activities are not scheduled for each day; they aresometimes used as a prep for the next day’s material or as a review of the previous day’s material.

Think About It activities are used to give students another direction from which to approach thematerial. They are similar to the Warm-Ups, but appear at the end of some lessons as a very briefreview of a major topic.

Practices are an immediate opportunity for students to answer questions about the material theyhave covered in that class. They are generally short-answer, true/false, multiple-choice, fill-in-the-blank, and short-answer questions designed to test student knowledge about the many concepts inthe section.

Reinforcement Activities are more detailed worksheets about the material covered in each section.While there may occasionally be time to use them in class, it is more likely that students will use themas homework or review outside of class. If you wish to incorporate some time during class to go over theanswers or to answer questions about the Reinforcement Activities, you may, but you might alsoconsider posting answer keys so students can check their work without cutting into class time.

Post-Tests occur at the end of each unit. The units cover anywhere from 3 to 4 days’ worth ofinstruction, but are generally broken up so that a post-test will be used every 3 or 4 days. Some classtime might also be spent going over the answers to these post-tests to give students an opportunity toreflect on what they have learned in each unit.

Best of luck!

Brian Pressley




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GOAL: To become familiar with Earth’s structure and ways to map its surface

WORDS TO KNOW

continental crust the crust below Earth’s landmasses, which is thicker than the oceaniccrust

contour lines lines on a topographic map that connect points of equal elevation

crust the outer skin of Earth, made of rocks, and containing all surface watersources

degrees the measure of a position on a circle; there are 360º in a circle

elevation the distance from sea level for an object above water

inner core the innermost layer of Earth; the inner core is composed of solid ironand nickel

isolines lines on a topographic map that connect points of equal elevation

latitude the distance in degrees north and south from Earth’s equator

longitude the distance in degrees of any point east or west from the primemeridian

magnetic declination the difference between true north and the magnetic north pole

magnetosphere Earth’s magnetic force field

mantle the second layer of Earth from the surface; the upper mantle is plasticand moves in convection cells

map projections maps that show the globe or an area on it as it would appear projectedonto a flat surface

map scale a method for showing how the measurement of the map relates to themeasurement of real Earth

Mercator projection a flat map in which meridians become parallel lines

meridians lines of longitude

minutes a division of degrees, used for greater accuracy in noting latitude andlongitude

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oceanic crust the crust below Earth’s oceans, which is thinner than the continentalcrust

outer core the third layer of Earth from the surface; the outer core is made ofmolten iron and gives rise to Earth’s magnetic field

parallels lines of latitude

polyconic projection a flat map that has greater accuracy at the poles than the Mercatorprojection

prime meridian the line of longitude that runs from the North Pole to the South Polethrough Greenwich, England

radioactive decay the breaking down of elements into other stable elements over time;radioactive decay gives off heat, which is one reason the interior of theplanet is hotter than the surface

silicates the mineral group that comprises most of the rocks on Earth

topographic type of map that shows the vertical distances of a landscape, such ashills and valleys

true north the geographic north pole

GRADE 8 • EARTH SCIENCEWhat Is Planet Earth?


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Earth’s Surface and InteriorSuppose you could view Earth from the Moon. To you, Earth would seem like a smooth, round,slowly spinning sphere. In fact, Earth is not a sphere. Because Earth spins, it bulges slightly at theequator. At the poles, Earth’s diameter is 12,714 kilometers. But at the equator, Earth’s diametermeasures 12,757 kilometers—just 43 kilometers more.

Why, then, does Earth seem smooth? After all, its highest mountain, Mt. Everest, rises to a heightof 8850 meters above sea level. Earth’s deepest valley is called the Mariana Trench. It drops to a depthof 11,033 meters below sea level. However, compared to the size of Earth, these are but tiny ripples onthe surface.

IN REAL LIFE

If Earth were the size of an apple, then Mt. Everest would be a tiny bump 0.025millimeters high. It would be too small for you to even notice!

Inside Earth

The outer surface of this huge spinning planet is the ground you walk on. Where the ground meetsair, all forms of life can be found. But Earth’s surface only tells part of the story. Geologists arescientists who study the ground beneath us. They have discovered that Earth’s surface is the top of athin outer crust. This thin crust is the first of four layers inside Earth.

How do geologists know what is inside Earth? The deepest mines only scratch the surface ofEarth’s crust. To find out what is inside, geologists study the vibrations set off by earthquakes.Earthquake waves travel through Earth. When these waves reach a layer of different material, some ofthem are bent, while others are slowed down. Geologists have learned the thickness, composition,and temperature of Earth’s four layers by comparing data collected from earthquakes all over the world.

The crust covering Earth is so thin that if Earth were an apple,the crust would be about the same thickness as the apple’s skin.There are 90 naturally occurring elements on Earth. Only eight ofthese make up 98.5% of Earth’s crust. These elements are oxygen,silicon, aluminum, iron, calcium, sodium, potassium, andmagnesium. These elements join together to form the minerals androcks that make up Earth’s crust.

The crust is thinnest, but densest, beneath the oceans. Thisoceanic crust is between 4 and 10 kilometers thick. It consistsmainly of a type of rock called basalt. Continental crust, the crust



Direct Instruction

Crust

Mantle

Outercore Inner

core

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below Earth’s land masses, is thicker, but lighter, than oceanic crust. It sinks deeper into the layerbelow (the mantle), but also rises higher above it. Continental crust can range anywhere from 35 to70 kilometers in depth. Granite and rocks similar to granite make up most of the continental crust.Below the top 20 meters, temperatures within Earth increase. Where the crust meets the next layer(the mantle), the temperature is about 500°C.

Beneath the crust is Earth’s biggest layer, the mantle. Themantle is about 2900 kilometers thick. It is made up mainlyof minerals called silicate minerals. Silicates are composed ofmetals, silicon, and oxygen. Some examples are quartz,feldspar, micas, garnet, and talc. Temperatures rise to 3000°Cin the lower mantle. The mantle is plastic, meaning it canmove slowly. You will learn more about moving rocks inBeneath the Crust, starting on page 526.

Beneath the mantle is the outer core. The outer core isEarth’s only liquid layer. It is made of nickel, iron, andpossibly several other elements. The outer core is about 2300kilometers thick. Where the outer core meets the inner core,temperatures are believed to be 3600°C. In the center ofEarth is the inner core. The inner core is a solid metal spheremade of iron and nickel. It is about 2700 kilometers in diameter and extremely hot. Temperatures atthe center of Earth are believed to be 4500°C. The inner core stays solid because of the intensepressure bearing down on it.

Why Earth Has Layers

Geologists believe that Earth’s layers separated because of their different densities. Shortly after Earthformed, 4.6 billion years ago, it was bombarded with meteorites. The impact of the meteoritescreated enough heat to melt some of Earth’s rocks. Once these rocks melted, the densest materialssank deep into Earth’s center. This is what formed the core. The lighter materials floated to the top,forming the crust. The mantle, in between the crust and the core, formed from what was left.

Earth’s Internal Heat

The high temperatures inside Earth come from several sources. Since Earth is slow to cool off, it stillcontains heat from the impact of meteorites long ago. Also, friction from movement within the crustcreates heat. Finally, some heavy elements found in the rocks are slowly decaying, or breaking down,into lighter, more stable elements. This process is called radioactive decay. As the elements decay,they also give off heat. However, Earth is not getting hotter. The heat created inside Earth is balancedby the heat escaping to the outside through volcanoes, geysers, and hot springs.



Direct Instruction

OxygenSilicon

Aluminum

IronCalcium

SodiumPotassium

MagnesiumOthers

Composition of Earth’s CrustComposition of Earth’s Crust


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THINK ABOUT IT 2

Look at the list of locations and their latitudes and longitudes. Then look at theirposition on the map, which is a Mercator projection. In finding the distance betweentwo places on this type of map, does a map scale work? Explain.



Direct Instruction

Latitude

32° 42' N

40° 47' N

22° 57' S

14° 40' N

51° 32' N

55° 45' N

19° 0' N

35° 40' N

34° 0' S

Longitude

117° 10' W

73° 58' W

43° 12' W

17° 28' W

0° 5' W

37° 36' E

72° 48' E

139° 45' E

151° 0' E

City

San Diego, CA

New York City, NY

Rio de Janeiro, Brazil

Dakar, Senegal

London, England

Moscow, Russia

Bombay, India

Tokyo, Japan

Sydney, Australia

75°

60°

45°

30°

30°

15°

15°

45°

0°

0° 30°30°60°90°120°150°180° 60° 90° 120° 150° 180°

New York

Rio de Janeiro

San Diego

Dakar

London

Bombay

Moscow

Tokyo

Sydney

NorthAmerica

Africa

Europe

Greenland

Asia

Australia

South America

City


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Fired UpEarth’s crust moves up and down as the downward pull of the crust interacts with the upward push ofthe mantle. You will see how these forces are balanced by watching how a change in the matter of anobject affects its ability to float.

Slowly push a common pin into the bottom of a birthday candle until the head of the pin isapproximately 2 mm from the bottom of the candle. Fill a 10-ounce glass full of water. Holding thecandle by the wick, place the candle in the water so that it floats upright. Mark a line on the glass toindicate the position of the bottom of the candle.

Use a long fireplace match, or attach a clothespin to the end of a regular match. (This is so you willnot burn your fingers!) Light the candle with the match, and extinguish the match. Every twominutes, mark a line on the side of the glass to indicate the position of the bottom of the candle.

1. What happened to the position of the bottom of the candle?

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2. As the candle melts, what happens to its weight?

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3. What is the relationship between weight and how high the candle floats?

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4. How does this model relate to changes in Earth’s crust and mantle?

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GRADE 8 • EARTH SCIENCEActivities


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GRADE 8 • EARTH SCIENCEHands-On Activities



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