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Delta Science Reader Erosion Delta Science Readers are nonfiction student books that provide science background and support the experiences of hands-on activities. Every Delta Science Reader has three main sections: Think About . . . , People in Science, and Did You Know? Be sure to preview the reader Overview Chart on page 13, the reader itself, and the teaching suggestions on the following pages. This information will help you determine how to plan your schedule for reader selections and activity sessions. L A E S U Reading for information is a key literacy skill. Use the following ideas as appropriate for your teaching style and the needs of your students. The After Reading section includes an assessment and writing links. © Delta Education. Photocopying and distribution prohibited. O VERVIEW F R O N O E P S R In the Delta Science Reader Erosion, students read about Earth’s structure. They find out about the slowly moving plates that make up Earth’s surface and how they are related to mountain building, trenches, earthquakes, and volcanoes. They learn about physical and chemical weathering and how they contribute to soil formation. They are introduced to the causes of erosion and deposition and the landforms that are the results of these forces. They also read about soil conservationists and the ways they work to conserve soil and control erosion. Finally, students learn about floods. Students will learn the layers and composition of Earth discover that landforms are the result of a combination of constructive and destructive forces explore the ways erosion, weathering, and deposition change Earth’s surface features examine nonfiction text elements such as table of contents, headings, and glossary interpret photographs and graphics to answer questions complete a KWL chart Delta Science Reader—Erosion 461 • Identify causes and effects of forces related to plate movements, earthquakes, weathering, and erosion • Draw conclusions about weathering and erosion • Identify main ideas and supporting details in text passages • Compare and contrast physical and chemical weathering • Demonstrate critical thinking • Interpret graphic devices • Summarize text information • Explain the steps in the process of cave formation NONFICTION TEXT ELEMENTS Erosion includes a table of contents, headings, photographs, captions, diagrams, boldfaced terms, and a glossary. The following terms are introduced in context and defined in the glossary: arch, barrier island, chemical weathering, continental glacier, convection, core, crust, delta, deposition, dune, earthquake, erosion, fertile, flood, floodplain, glacial till, glacier, gravity, groundwater, humus, landforms, mantle, mass movement, mineral, moraine, oxbow lake, physical weathering, plates, rock, runoff, sandbar, sea-floor spreading, sediment, sinkhole, soil, soil horizon, soil profile, stack, subduction, valley glacier, volcanic island, volcano, weathering. R O Read the title aloud, and invite students to share what they know about the topic from their personal experiences and hands-on explorations in science. To stimulate discussion, ask questions such as these: What happens to things that are left outside, unprotected from the weather? How do you think wind, rain, ice, and snow affect things in nature, such as rocks? What kinds of changes might weather cause in Earth’s surface features? L A E S U N O Begin a group KWL chart by recording facts students know about erosion in the K column. You may want students to copy the KWL chart so they can maintain their own charts as they read. S R E P CONTENT VOCABULARY cover? (a rock formation; a rocky or desert landscape; a rock or cliff with a hole carved in it) How do you think this rock shape was formed? (Accept all ideas.) You may wish to explain that the photograph shows a natural rock formation in Arches National Park in Utah. The rock shape is one of more than 1,500 sandstone arches and “windows” in the park. As students read the book, they will find out how forces of nature worked to create such formations. K W L + What I Know What I Want to Know What I Learned What I Want to Explore Further F BEFORE READING Build Background Access students’ prior knowledge of erosion by displaying and discussing the cover. Ask, What do you see in the photograph on the 462 broward county hands-on science Preview the Book Explain that when students preview nonfiction, they should look at the title, the table of contents, headings, boldfaced words, photographs, illustrations, charts, graphics, and captions. Then preview the book with students. Call attention to the various nonfiction text elements and explain how they can help © Delta Education. Photocopying and distribution prohibited. READING IN THE CONTENT AREA SKILLS questions on the KWL chart to set an overall purpose for reading. students understand and organize what they read. Ask questions such as these: How do the headings help you predict what you will read about? What do you see in this picture? How do you think it will help you understand the text? Explain that the words in boldface type are important words related to erosion. Point out that these words are defined in the glossary. Choose one word and have students find its definition in the glossary. GUIDE THE READING Preview the book yourself to determine the amount of guidance you will need to give for each section. Depending on your schedule and the needs of your class, you may wish to consider the following options: • Whole Group Reading Read the book aloud with a group or the whole class. Encourage students to ask questions and make comments. Pause as necessary to clarify and assess understanding. Conclude the preview by inviting students to suggest questions they would like to have answered as they read the book. Tell them to add the questions to the W column of the KWL chart. Preview the Vocabulary You may wish to preview some of the vocabulary words before reading, rather than waiting to introduce them in the context of the book. Possibilities include creating a word wall, vocabulary cards, sentence strips, or a concept web. E P R O © Delta Education. Photocopying and distribution prohibited. earthquake F • Independent Reading Some students may be ready to read independently. Have them rejoin the class for discussion of the book. Check understanding by asking students to explain in their own words what they have read. Tips for Reading glacier • If you spread out the reading over several days, begin each session by reviewing the previous day’s reading and previewing what will be read in the upcoming session. forces of change erosion weathering flood L A N O S R For example, many words are related to forces that affect Earth’s surface features, or landforms. Develop a web like the one that follows. E S U • Shared Reading Have students work in pairs or small groups to read the book together. Ask students to pause after each text section. Clarify as needed and discuss any questions that arise or have been answered. volcano Concept web for forces of change. Set a Purpose Discuss with students what they might expect to find out from the book, based on their preview. Encourage them to use the • Begin each text section by reading or having a volunteer read aloud the heading. Have students examine any illustrations or graphics and read accompanying captions and labels. Discuss what students expect to learn, based on the heading, illustrations, and captions. • Help students locate context clues to the meanings of words in boldface type. Remind them that these words are defined in the glossary. Provide help with words that may be difficult to pronounce. Delta Science Reader—Erosion 463 gap? (No, hot magma pushes up between the plates and forms new crust.) What is this process called? (sea-floor spreading) What two effects can happen when one plate bumps or crashes into another? (One plate can slide up over the other, forming a mountain range and a deep ocean trench. The two plates can be forced together, pushing up blocks of crust and forming a mountain range.) What is the process called when one plate sinks under another plate? (subduction) Point out the prefix sub- and ask students what they think it means. (under) Can they think of other words with the prefix sub-? (submarine, subway, suburb, subtotal, subtract) • As appropriate, model reading strategies students may find helpful for nonfiction: adjust reading rate, ask questions, paraphrase, reread, visualize. Think About . . . (pages 2–13) Pages 2, 3 What Is Earth’s Structure? Layers, Moving Plates • Check comprehension by asking, What are Earth’s three main layers? (the crust, the mantle, and the core) How many layers does the core have? What are they? (two, the outer core and the inner core) What do you notice about the thickness of the crust compared to the rest of Earth’s layers? (The crust is very thin.) Then have students read the section titled “Layers” on page 2. E P R O F • Then have students finish reading pages 2 and 3 and study the diagrams at the bottom of page 3. Assess comprehension by having students summarize the main ideas about plates. (Earth’s surface is made up of separate moving sections called plates. Convection in the mantle forms convection currents that make the plates move. The slowly moving plates cause changes in Earth’s surface, especially at plate boundaries.) • Ask, What happens when plates move away from each other? Do they leave a 464 broward county hands-on science L A N O • If necessary, provide help with the pronunciation of Celsius (SEL-see-us) and Fahrenheit (FAIR-uhn-hite). S R • Ask, What is the main idea—the most important point—about the crust on page 2? (The crust covers Earth’s entire surface.) What details support this main idea? (The crust is Earth’s rocky outer layer; the continents and the oceans are on the crust.) E S U • Check comprehension by having students explain what is happening in each of the diagrams at the bottom of the page. How did the diagrams help you understand these processes? (They show in pictures what the text describes in words.) Further Facts • The idea that the continents have changed position—which led to the theory of plate tectonics—was first proposed in 1912 by a German scientist named Alfred Wegener (1880–1930). He suggested that at one time the existing continents were joined together as one supercontinent, which he called Pangaea, meaning “all lands.” • Pangaea began to split up about 200 million years ago. The continents continue to move. Europe and North America are estimated to be moving apart about 2–4 cm (about 0.75—1.5 in.) a year. Page 4 Earthquakes and Volcanoes • Before students read page 4, invite them to share what they know about earthquakes and volcanoes. Then have them read the section on earthquakes. © Delta Education. Photocopying and distribution prohibited. • Generate interest in the text by asking, What do you think is inside Earth? Explain, Long ago, people had no way of knowing what Earth was like inside. Today, scientists have instruments that have given us a good idea of Earth’s insides. Have students view the diagram of Earth’s inner structure on page 2 and read the caption and labels. After reading, discuss the causes and effects of earthquakes. Ask, What can happen when pressure bends or cracks a plate? (It can cause an earthquake.) What effect did an earthquake have on the road in the photograph? (The earthquake caused a wide, deep crack to form in the road.) Where do some earthquakes happen? (at boundaries where plates slide past or push against each other) • Next, have students read the section on volcanoes. Point out that volcanoes both destroy and create Earth’s landforms. Ask, How do volcanoes destroy landforms? (They can blow off the tops of mountains.) How do volcanoes create landforms? (Lava hardens and builds up land. Volcanoes under the ocean can form volcanic islands. The mid-ocean ridge is a volcanic mountain chain. All new ocean floor comes from volcanoes.) © Delta Education. Photocopying and distribution prohibited. S R F R O E P • There are about 1,500 historically active volcanoes in the world. Some estimates of the number of undersea volcanoes exceed 1 million. • Most of Earth’s active land volcanoes are in a circle around the Pacific Ocean. Many earthquakes also take place here. This area is called the Ring of Fire. The reason there are so many volcanoes and earthquakes in the Ring of Fire is that this is where many of Earth’s plates meet the Pacific Plate. • Before having students read page 5, write the term weathering on the board. Ask students what they notice about the word. (It has the word weather in it.) Explain that weathering is the term used for a force that can change rocks. Invite students to speculate on what is involved in weathering. (Accept reasonable responses. Students should infer that weathering may involve certain weather conditions.) E S U • Have students read the introduction on page 5. Ask, What is weathering? (the breaking down of rocks into smaller pieces) What natural forces are involved in weathering? (wind, water, temperature changes, plants) What are the two kinds of weathering? (physical weathering and chemical weathering) L A N O Further Facts • Chains of volcanoes can form over hot spots—very hot places deep in Earth’s mantle—as a moving plate slides across the hot spot. This is how the Hawaiian Islands were formed. The islands at the northwest end of the chain formed first. Other islands formed as the Pacific Plate continued moving northwest. A new volcano growing on the ocean floor southeast of the island of Hawaii (the Big Island) may someday become another island in the state. It is already named: Loihi. Page 5 What is Weathering? and Physical Weathering • Have students read page 5 to find out about physical weathering. Assess understanding by having students summarize how each natural force causes changes in rocks. (Running water tumbles rocks around and breaks them up. Wind blows sand against rocks and wears away the rock. Temperature changes cause water in rocks to freeze and break the rocks apart. Plant roots can grow into cracks and break rocks apart.) Page 6 Chemical Weathering • Have students examine the photographs on page 6 and read the captions. Then have them read the text to learn about chemical weathering. After they read, have them compare and contrast physical and chemical weathering. Ask, How are physical and chemical weathering alike? (They both break down rocks.) How are they different? (In physical weathering, rocks are broken down by natural physical processes and forces, such as water freezing and melting in cracks, rocks being tumbled by water, wind blowing sand against rocks, and plants growing in cracks. In chemical weathering, water, Delta Science Reader—Erosion 465 the movement of weathered rock and soil by water, ice, and wind.) What conclusion can you draw about how long it takes for weathering and erosion to change Earth’s surface? (The process takes a very long time.) oxygen, and acids change the chemical makeup of rocks and break them down.) • If necessary, provide help with the pronunciation of oxygen (OK-sih-juhn), carbon dioxide (KAR-buhn die-OK-side), lichens (LIE-kenz), and acidic (uh-SID-ik). Page 7 Soil Formation • Have students read about soil formation on page 7 and study the cutaway diagram of a soil profile. Ask, What is soil mostly composed of? (weathered rock) What else does soil contain? (decayed plant and animal material, called humus, and water and air) To check comprehension, have students summarize the three main layers of soil and what each is made of. (topsoil, made of sand, silt, clay, and humus; subsoil, made of bits of rock mixed with a little humus; parent layer, made of large pieces of rock with no humus) Ask, What is another name of layers of soil? (soil horizons) Why do you think no plants or animals live below the subsoil? (Students may recognize that without humus, the parent material lacks enough of the right kind of nutrients to support life.) • Contrast some of the very slow processes of weathering, erosion, and deposition with the rapid earth-changing events students have read about: volcanoes and earthquakes. As students read the next sections about different forces of erosion, tell them to think about whether the forces work quickly or slowly to reshape the land. R O F • If necessary, provide help with the pronunciation of humus (HYOO-muhs). Page 8 What Causes Erosion and Deposition? • Have students read page 8, study the photographs, and read the captions to learn about erosion and deposition. Ask, What is the difference between weathering and erosion? (Weathering is the breaking down of rocks by wind, water, and other natural forces. Erosion is 466 broward county hands-on science L A N O S R E P E S U • What are the results of weathering and erosion? (The shape of the land is changed. Some of Earth’s landforms are created by weathering and erosion.) Discuss the definition of landforms as shapes or features of Earth’s surface. Make a class list of landforms students have seen or know about. Decide which are the primarily caused by weathering and erosion. (Students may suggest valleys, canyons, gullies or ravines, stone arches such as those shown on the cover, mesas, sand dunes, cliffs, or caves.) • Point out that landforms are the result of a combination of constructive and destructive forces. Ask, What do you think the term destructive force means? Give an example. (A destructive force is one that breaks down material or is harmful to the land, as when chemical weathering wears away rock to create a cave or when windblown sand carves a rock formation like the one on the cover.) What do you think the term constructive force means? Give an example. (A constructive force is one that builds up or makes something new, or is helpful for the land, as when a volcano makes a new island or a mountain range is built at a plate boundary.) Page 9 Running Water • Have students read the text about running water on page 9. Ask, What is the main © Delta Education. Photocopying and distribution prohibited. • Have students describe the steps in the process by which chemical weathering creates huge underground caves. (Rainwater and carbon dioxide mix together and create weakly acidic groundwater. The acid dissolves parts of rocks underground. The holes in the rocks get larger and larger, forming caves.) idea of this section? (Moving water is a main cause of erosion.) What three main things affect the amount of erosion a stream or river causes? (how steep the land is, the number and type of plants on the land, the amount of water that is moving) How do plants slow down erosion? (Their roots hold the soil in place.) What conclusion can you draw from this about land that has been cleared for farming or another purpose? (Students may realize that cleared land is more vulnerable to erosion than uncleared land.) • Ask, What are some ways in which erosion and deposition create landforms? (Rivers wear away rock, forming valleys and canyons. Winding rivers can change course and form oxbow lakes. Sediments dropped by rivers when they enter the ocean settle to the bottom and form new land called deltas.) © Delta Education. Photocopying and distribution prohibited. F • If necessary, provide help with the pronunciation of deposition (deh-puh-ZIHshuhn). Page 10 Waves • Have students read the text about waves on page 10 and look at the photographs and captions. Ask, How do waves both destroy and create landforms? (Waves wear away rock, creating sea cliffs and forming arches. Waves carry sand and pebbles from one place to another. Sand deposited by waves can form sandbars and barrier islands. Stones deposited by waves form rocky beaches.) • Have students summarize the different types of mass movement. (rockslides, when gravity causes loose rocks to fall; mudflows, or rivers of mud; slumping, when soil and plants move together as a mass; creep, which is very slow mass movement) E S U L A • Before students read the section on groundwater, review with them what they learned about chemical weathering on page 6. Ask, What happens when water in the ground mixes with carbon dioxide? (It forms a weak acid that dissolves rock and can hollow out underground caves.) Ask whether any students have ever toured a cave, and invite them to share their observations. Explain that students will learn more about the effects of groundwater when they read page 12. Then have them read the paragraphs under “Groundwater.” Ask, How does groundwater cause deposition? (When groundwater becomes less acidic, it deposits the rock that was once dissolved in it.) What is the result of this kind of deposition? (As the water drips, it creates stalactites that hang down from the ceiling of a cave and stalagmites that build up on the floor.) N O S R R O • Have students read the text about gravity and mass movement on page 11. Ask, What is mass movement? (the movement of large amounts of rock and soil downhill) How is gravity related to mass movement? (Gravity causes mass movement.) Pages 12, 13 Groundwater, Wind, and Glaciers • Students may be interested to know the origins of the terms oxbow lake and delta. Explain that both names are related to the shape of the landform. An oxbow lake resembles an oxbow—a U-shaped frame attached to a yoke for a team of oxen; the oxbow forms a collar for the ox’s neck. A river delta is triangular in shape, resembling the uppercase form of delta, the fourth letter of the Greek alphabet: Δ. E P Page 11 Gravity and Mass Movement • Invite students to speculate how wind causes erosion and deposition. Students may suggest that wind picks up sand and dust in one place and drops it in another. Have them read the section about wind on pages 12 and 13 to confirm their ideas. Then ask, How does wind cause erosion? (It picks up and carries away dust and sand Delta Science Reader—Erosion 467 them about the drought and dust storms of the 1930s, when wind picked up and carried away the soil. Ask, What can slow down soil erosion? How? (plants; their roots hold soil in place) and deposits them in another place. Wind blasts rocks with the sand it carries and grinds them down.) What is one type of landform formed by wind? (sand dunes) • Have students read the section on glaciers on page 13. Ask, What is a glacier? (a huge moving body of ice) What is the difference between a valley glacier and a continental glacier? (A valley glacier is like a river of ice; a continental glacier is a sheet of ice that covers large areas of land.) How do glaciers change Earth’s surface? (They wear away rocks and move soil and rocks to new places.) You may want to explain that there have been at least six periods in Earth’s history when much of Earth’s surface was covered with ice. We call these periods ice ages. • After students read, have them confirm the inferences they made. Ask, What do soil conservationists do? (They work to prevent and control erosion of soil.) Have students summarize some of the methods soil conservationists have developed. (strip cropping, or planting two different crops side by side; leaving stubs of plants in fields after crops are harvested; planting windbreaks; grading stream banks; and placing rocks and plants along the banks) About Floods N O • Have students read page 15 to learn about floods. After they read, ask, Why do you think most flooding in the United States occurs in the spring? (That is when snow that falls in the mountains during the winter melts and flows into streams and rivers.) S R R O E P • If necessary, provide help with the pronunciation of stalactites (stuh-LAKtites), stalagmites (stuh-LAG-mites), Antarctica (ant-ARK-tih-kuh), and moraine (moh-RANE). F People in Science (page 14) Soil Conservationists • Before students read, ask whether they know what a conservationist is. (a person who works to save endangered things) Ask, What do you think a soil conservationist does? (works to save soil) Have students make inferences about the need for soil conservation, based on what they have read about erosion. If necessary, remind 468 broward county hands-on science L A Did You Know? (page 15) E S U • Point out that floods are another force that is both destructive and constructive. Ask, How do floods destroy? (They flood houses, wash away roads and bridges, drown crops, and harm or kill people and wildlife.) How are floods helpful? (They deposit new, fertile sediment on a river’s floodplain.) Further Facts • Levees—embankments built along the edges of a stream or river—are an ancient method of flood control that is still being used. The ancient Egyptians built a series of levees along the Nile River for more than 966 km (600 mi). • One of the largest levee systems today is the one built along the Mississippi River. It was begun by French settlers in the early eighteenth century. Today the system © Delta Education. Photocopying and distribution prohibited. • You may wish to tell students that because of the huge dust storms that struck the central United States in the 1930s, the area was called the Dust Bowl. The natural grasslands had been plowed under in order to plant wheat. When the drought killed the wheat, the exposed topsoil was carried off by the wind. Thousands of families were forced to leave their homes. The problem was eventually brought under control after windbreaks were planted and some of the native grassland was restored. includes more than 11,200 km (7,000 mi) of levees. Some levees reach 15 m (50 ft) in height. • Another method of flood control is the construction of artificial channels. The Los Angeles River, which runs through that city’s downtown, is contained by a concrete channel. While protecting the city from flooding, the channel has taken away the natural beauty of the river. AFTER READING Complete the KWL chart you began with students before reading by asking them to share the answers to their questions. Call on volunteers to retell each text section. Then have students use the information in the KWL chart to write brief summary statements. © Delta Education. Photocopying and distribution prohibited. L A Present the following as writing assignments. N O S R F E S U Writing Links/Critical Thinking Discuss with students how using the KWL strategy helped them understand and appreciate the book. Encourage them to share any other reading strategies that helped them understand what they read. Direct attention to the fourth column in the chart and ask: What questions do you still have about erosion? What would you like to explore further? Record students’ responses. Then ask, Where do you think you might be able to find this information? (Students might mention an encyclopedia, science books, and the Internet.) Encourage students to conduct further research. R O 3. What are the six main causes of erosion and deposition? (running water, waves, gravity and mass movement, groundwater, wind, glaciers) 4. What is mass movement, and what causes it? (Mass movement is the movement of large amounts of rock and soil downhill. It is caused by gravity.) Summarize E P 2. What slow processes cause changes in Earth’s surface, and how do they do this? (Weathering breaks rocks down into smaller pieces. Chemical weathering can wear away rocks and create caves. In erosion, water, ice, and wind move weathered rock and soil from one place to another.) Review/Assess Use the questions that follow as the basis for a discussion of the book or for a written or oral assessment. 1. What fast processes cause changes in Earth’s surface, and how do they do this? (Earthquakes shake the ground and can cause landslides and cracks in Earth’s surface. Volcanic eruptions can blow off the tops of mountains; lava flows build up land. Other fast processes include rockslides, mudflows, floods, slumps, and wave action during a major storm.) 1. You have learned that landforms are the result of a combination of constructive and destructive forces. Describe how these forces affect Earth’s surface features. (Students should mention that constructive forces include volcanic eruptions, which create new land and can form volcanic islands, and deposition of sediment. Destructive forces include weathering and erosion, which break down rocks into smaller pieces.) 2. The text states that the main cause of erosion is running water. Think about the various causes of erosion described. Why do you think running water is a more powerful force than waves, gravity, groundwater, wind, and glaciers? (Students may recognize that running water in the form of rain, runoff, and streams occurs in most places on Earth and affects surface features. Waves affect only seashores, gravity can work only on material that has already been weathered, groundwater affects only underground materials, wind is not constant, and glaciers occur in only a few places on Earth.) Delta Science Reader—Erosion 469 Science Journals: You may wish to have students keep the writing activities related to the Delta Science Reader in their science journals. References and Resources For trade book suggestions and Internet sites, see the References and Resources section of this teacher’s guide. R O F 470 broward county hands-on science © Delta Education. Photocopying and distribution prohibited. N O S R E P L A E S U Delta Science Reader Solar System Delta Science Readers are nonfiction student books that provide science background and support the experiences of hands-on activities. Every Delta Science Reader has three main sections: Think About . . . , People in Science, and Did You Know? Be sure to preview the reader Overview Chart on page 14, the reader itself, and the teaching suggestions on the following pages. This information will help you determine how to plan your schedule for reader selections and activity sessions. L A E S U Reading for information is a key literacy skill. Use the following ideas as appropriate for your teaching style and the needs of your students. The After Reading section includes an assessment and writing links. © Delta Education. Photocopying and distribution prohibited. OVERVIEW F R O N O E P S R In the Delta Science Reader Solar System, students take a tour of the Sun and the nine planets. Other space objects such as comets, asteroids, and meteoroids are explored. Students read about the rotation and revolution of the planets and the causes of night and day, seasonal changes, and the phases of the Moon. The book describes the work of a planetary geologist. In addition, students discover how telescopes work. Students will: discover facts about the Solar System explore the planets and other objects in the Solar System discuss the function of a table of contents, headings, and a glossary interpret photographs and graphics to answer questions complete a KWL chart organize information in a variety of ways Delta Science Reader—Solar System 471 • Compare and contrast planets • Determine the main idea of a paragraph • Recognize cause-effect relationships related to planetary conditions • Draw conclusions about planetary facts • Demonstrate critical thinking • Interpret graphic devices • Summarize • Categorize planets To stimulate discussion, ask questions such as these: What are some of the objects in our Solar System? How many planets are there? What is Earth’s closest neighbor in space? Begin a class KWL chart by recording facts students know about the Solar System and its planets in the K column. You may wish to copy the KWL chart and ask students to maintain their own charts as they read. K W L What I Know What I Want to Know What I Learned NONFICTION TEXT ELEMENTS Solar System includes a table of contents, headings, photographs and illustrations, captions, diagrams, boldfaced terms, a biographical sketch, and a glossary. The following terms are introduced in context and defined in the glossary: asteroid, astronomer, atmosphere, axis, comet, crater, day, Earth, ellipse, gas giant, gravity, inner planet, Jupiter, Mars, Mercury, meteor, meteorite, meteoroid, moon, Moon, Neptune, orbit, outer planet, phase, planet, Pluto, revolution, revolve, rotate, satellite, Saturn, solar, solar system, space probe, star, Sun, telescope, Uranus, Venus, year. R O E P F BEFORE READING Build Background Access students’ prior knowledge of the Solar System and its planets by displaying and discussing the cover. Ask, Do you know what planet this is? (Saturn) What do you think these other objects are? (some of Saturn’s moons) Then read the title aloud and invite students to share what they know about the topic from their personal experiences and prior hands-on explorations in science. 472 broward county hands-on science E S U N O Preview the Book Take a few minutes to have students look through the book. Explain the steps involved in previewing nonfiction: think about the title, read the table of contents, read the headings, read boldfaced words, and examine any photographs, illustrations, charts, and graphics. S R CONTENT VOCABULARY L A + What I Want to Explore Further Call attention to the various nonfiction text elements and explain how each feature can help students understand what they read. Point out that the table of contents lists all the main headings in the book and their page numbers. Ask, How do the headings help you know what you will learn about? Point to some of the photographs and ask questions such as: What does this photo show you? How do you think it will help you understand the text? Explain that the words in boldfaced type are important words related to our Solar System that students will learn when they read the book. Point out that these words are defined in the glossary. Choose one word and have students find its definition in the glossary. © Delta Education. Photocopying and distribution prohibited. READING IN THE CONTENT AREA SKILLS • Shared Reading Have students form pairs or small groups and read the book together. Ask students to pause after each text section. Clarify the text as needed. Discuss any questions that arise or have been answered. Following the preview, ask, What questions do you have about our Solar System that you would like this book to answer? Record students’ responses in the W column of the KWL chart. Explain that they will add to the chart as they are reading and complete it when they finish reading. Preview the Vocabulary You may wish to preview some of the vocabulary words before reading, rather than waiting to introduce them in the context of the book. Possibilities include creating a word wall, vocabulary cards, sentence strips, or a concept web. For example, have students categorize words. List words from the glossary that can be grouped in different ways, such as moon, asteroid, revolve, comet, planet, and rotate. After helping students define the words, ask, Into what groups can we put these words? What would be a good name for each category? (Objects in Our Solar System— asteroid, comet, moon, planet; Ways Planets Move—revolve, rotate) Set a Purpose © Delta Education. Photocopying and distribution prohibited. Discuss with students what they might expect to find out when they read the book, based on their preview. Encourage them to use the questions on the KWL chart to set an overall purpose for reading. F R G O UIDE THE READING Preview the book yourself to determine the amount of guidance you will need to give for each section. Depending on your schedule and the needs of your class, you may wish to consider the following options: • Whole Group Reading Read the book aloud with a group or the whole class. Encourage students to ask questions and make comments. Pause as necessary to clarify and assess understanding. Tips for Reading E S U • If you spread out the reading over several days, begin each session by reviewing the previous day’s reading and previewing what will be read in the upcoming session. L A • Begin each text section by reading or having a volunteer read aloud the heading. Discuss what students expect to learn, based on the heading. Have students examine photographs, illustrations, and graphics and read accompanying captions and labels. N O S R E P • Independent Reading Some students may be ready to read independently. Have them rejoin the class for discussion of the book. Check understanding by asking students to explain in their own words what they read. • Help students locate context clues to the meanings of words in boldface type. Remind them that these words are defined in the glossary. Provide help with words that may be difficult to pronounce. • As appropriate, model reading strategies students may find helpful for nonfiction: adjust reading rate, ask questions, paraphrase, reread, visualize. Think About . . . (pages 2–13) Pages 2–3 Our Solar System • Direct students’ attention to the diagram of the Solar System on page 2. Ask questions to elicit facts about the Solar System. How many planets are there? (nine) Which one is closest to the Sun? (Mercury) Which is the farthest? (Pluto) Where is Earth in the Solar System? (third from the Sun) Which is the biggest planet? (Jupiter) Which is the smallest? (Pluto) Delta Science Reader—Solar System 473 • Generate interest in the text by asking, As you sit here, are you moving or staying still? Explain, Everyone on Earth is moving—because the Earth itself is moving! We’re being carried along by the Earth as it turns on its axis and as it travels around the Sun. Have students read page 2 to find out about our Solar System and the ways in which the Earth moves. Further Facts • Check comprehension by asking, What is our Solar System? (the Sun and everything that moves around it) What is the difference between revolving and rotating? (Revolving is moving in a path around something; rotating is turning on an axis.) Saturn Roman god of agriculture and time Mercury messenger of the ancient Roman gods Venus Roman goddess of love and beauty Mars Roman god of war Jupiter king of the Roman gods Neptune Roman god of the sea E P R O F • If necessary, provide help with the pronunciation of Mercury (MER-kyuhree), Jupiter (JOO-puh-tur), Uranus (YOOR-un-uhss), and ellipse (i-LIPS). L A Pluto Roman god of the underworld, the land of the dead N O Page 3 What Is the Sun Like? • Before reading “What Is the Sun Like?” have students study the photograph of the Sun. Invite volunteers to describe what they see. Have students read the caption to find out about the Sun’s size and some of its features. Ask, What is shown coming off the Sun’s surface? (cloud of matter erupting) You may wish to share with students that these giant eruptions of matter are called solar prominences. Ask, What are the light and dark areas shown on the Sun? (The light areas are hotter places, and the dark areas are cooler places.) S R • Before reading the first paragraph on page 3, have students read the caption at the top and study the diagram of the Sun and the Earth. Discuss what the diagram shows. Ask, When it is summer in the northern part of the world, what season is it in the southern part of the world? (winter) Read the paragraph below the diagram. Ask, How does the diagram help you understand the text? (It shows in picture form what the words describe.) E S U Uranus the sky personified as a god and father of the Titans (a family of giants) in Greek mythology • Have students read the text about the Sun on page 3. Ask, Why is the Sun so important for life on Earth? (It provides heat and light.) Point out that most living things get their food energy from green plants. Green plants use the Sun’s energy to make this food. • Check understanding by asking, What is a star? (a huge ball of glowing gas that produces light and heat) As appropriate, tell students that the Sun is an average star in terms of its 474 broward county hands-on science © Delta Education. Photocopying and distribution prohibited. Discuss with students the meaning of the word system. (a group of objects that work together as one unit) Discuss that in a system, the parts usually have an effect on one another. Ask, What would happen if the Sun were removed from the Solar System? (The planets would fly off into space, because there would not be enough gravity to keep them in orbit.) The planets were named after ancient mythological characters: but it is different from Earth in many ways. What are some of the differences? (Venus rotates in the opposite direction; its day lasts 243 Earth days; it is covered with clouds; it is much hotter.) temperature and the material that it is made of. In terms of its mass, the Sun is a fairly large star. In fact, it is the central and largest body in the Solar System. Most of the mass (99.8 percent) in the Solar System is in the Sun. Venus is the easiest planet to see without the aid of a telescope. It can be seen in the direction of the Sun, near the horizon, just before sunrise or just after sunset. Because of this, we sometimes call Venus the morning or evening star. • Ask, What is the most surprising thing you learned from reading this section? (Responses will vary.) Page 4 The Inner Planets: Mercury • Have students read the introduction. Then discuss the Mercury Facts feature with them. You may wish to use the facts provided to begin a nine-column Planetary Facts table that contains information about all nine planets. Explain, A table is a good way to organize information. It makes facts easy to read and compare. • Have students read page 4 to find out about Mercury. Ask, Why do you think Mercury takes less time than any other planet to revolve around the Sun? (It is the planet closest to the Sun and has a shorter distance to travel.) Why can’t Mercury be seen at night? (Students may infer that because Mercury is between Earth and the Sun, the night side of Earth faces away from it.) Why do you think Mercury gets so hot during the day and so cold at night? Explain that Mercury has no atmosphere around it to trap heat, so it gets very hot while the Sun is shining, but loses its heat quickly when the Sun sets. © Delta Education. Photocopying and distribution prohibited. F R O • If necessary, provide help with the pronunciation of atmosphere (AT-muhss-fihr). Page 5 Venus • Discuss the Venus Facts with students and add the facts to the table. Ask, What do you notice about the length of a day and a year on Venus? (A day lasts longer than a year.) • Have students read page 5. Then say, Venus is sometimes called Earth’s twin, Page 6 Earth L A E S U • After discussing the Earth Facts with students, add the facts to the table. Point out that the year is 365 1/4 days long. Ask, What happens to that extra quarter of a day? If necessary, explain that we add a day to our calendar every four years. We call the year in which that takes place a Leap Year. N O S R E P • If necessary, provide help with the pronunciation of carbon dioxide (KAR-buhn dye-OK-side). • Read the first paragraph and ask, What is the main idea—the most important idea—expressed in this paragraph? (Earth is the only planet that has the atmosphere, water, and temperature that most living things need.) What conclusion can you draw from this? (Earth is the only planet that people can live on.) • Ask students to examine the diagram on page 6, then read the text. Ask, What did you learn by studying the diagram and reading the text? (how day and night are caused) What is the name for Earth’s movement that causes day and night? (rotation) Page 7 Earth’s Moon • Have students look at the photograph of the Moon on page 7. Before reading the text, invite students to share what they know about the Moon. Remind students that our knowledge of the Moon comes not only from telescopes and space Delta Science Reader—Solar System 475 • Ask students to read the text on page 7 and examine the diagram of the Moon’s phases. Guide them to see that when the Moon is between the Earth and the Sun, it is difficult to see because the side facing us is dark. When the Moon is to one side of the Sun, we see a crescent or half moon. When the Moon is exactly opposite the Earth and the Sun, it is full. Ask, Did you find the diagram helpful? Try explaining in words what the diagram shows. Which do you think is the better way of presenting this information? Why? (Students will probably say the diagram is the better way because you can quickly see what causes the changes; an explanation in words takes longer.) Page 8 Mars • Discuss the Mars Facts with students and add them to the table. Show students how they can use the table to compare and contrast the inner planets. Say, Think about the facts about the surfaces of the inner planets. What do they all have in common? (rocky crust, plains, high places, craters) What type of landform is found on many of the inner planets? (volcanoes) Mars’s Olympus Mons is the largest volcano in the Solar System. It is 24 kilometers (about 15 miles) high and 600 kilometers (about 372 miles) across. N O • Encourage students to use the diagram of views of the Moon from Earth to determine the meanings of waxing and waning. Students should be able to see that the lighted portion of the Moon’s surface that we see increases in size when the crescent is waxing and decreases when it is waning. Explain that gibbous means that more than half but not all of the Moon’s disk is lighted. • Ask, Why do you think so many space probes have been sent to Mars? Explain, if needed, that Mars used to be much like Earth, and scientists have been trying to find signs that it once had life. Have students draw conclusions about whether people could live on Mars without special equipment. (No, because the air doesn’t have much oxygen; it is also very cold.) • Point out that, like the Earth and the Moon, most objects in the Solar System move in regular and very predictable ways. Because of this, we can predict the length of each day and year, the phases of the moon, and when events like solar and lunar eclipses may happen. • You may wish to tell students that the names of Mars’s moons mean “fear” (Phobos) and “panic” (Deimos). They were named after the two sons of the god Mars in Greek mythology. R O F • If necessary, provide help with the pronunciation of gibbous (GIB-us). 476 L A • Read the text and caption on page 8. Tell students that although there may be no liquid water on the surface of Mars now, scientists believe that the planet once had rivers and oceans as Earth does. S R E P E S U • Direct students to look at the photograph of Mars. Ask, Why do you think Mars is called the “Red Planet”? (The rocks and soil look red.) broward county hands-on science • If necessary, provide help with the pronunciation of Sojourner (SOH-jerner), Phobos (FOH-buhss), and Deimos (DEE-muhss). © Delta Education. Photocopying and distribution prohibited. probes; astronauts actually landed on the Moon and brought back Moon rocks. The Moon is the only planetary body that people have visited. On July 20, 1969, Neil Armstrong and Buzz Aldrin became the first people to walk on the Moon. Six U.S. spacecrafts (Apollos 11, 12, 14, 15, 16, and 17) landed on the Moon between 1969 and 1972. Page 9 The Outer Planets: Jupiter common? (both have strong winds and storms, both give off more heat than they get from the Sun) What conclusion can you draw from the fact that Jupiter and Saturn give off more heat than they receive from the Sun? (They produce their own heat.) • Read the introduction with students. You may wish to tell students that not long ago, Saturn was the only planet known to have rings. • Discuss the Jupiter Facts on page 9 and add them to the table. Explain that almost four hundred years ago a scientist named Galileo used a telescope to observe the night sky. In 1610, he saw Jupiter’s four largest moons. The known number of Jupiter’s moons increased as space probes or improvements in telescopes provided us with more information. In 2002, astronomers found 11 new moons, bringing the total to 39. • Read the text on page 9. Ask students to describe what Jupiter looks like in the photograph. Ask, How is Jupiter’s appearance different from that of the inner planets? (It does not have craters, mountains, and other landforms.) Explain that scientists believe that Jupiter has a liquid metal interior with a rocky core. © Delta Education. Photocopying and distribution prohibited. F R O E P • Read and discuss the Uranus Facts on page 11 and add them to the table. Ask, What do you notice about the length of the planets’ years? (They keep getting longer.) What is the cause of this? (Each planet is farther away from the Sun and has a longer distance to travel to go around it.) L A E S U • Read the text on page 11. Remind students that they learned that almost all of the planets have a tilted axis. Tell them that Uranus’s axis is so tilted (97.9 degrees) that the planet circles the Sun lying on its side. Since it takes 84 years to complete one orbit, Uranus’s polar regions each have 42 years of darkness and 42 years of light. Uranus, like Venus and Pluto, also rotates “backward,” or clockwise, instead of counterclockwise. N O S R Jupiter’s Great Red Spot is located in the lower right of the photograph. The small black spot in the lower left of the photograph is actually the shadow of Europa, one of Jupiter’s moons. Page 11 Uranus • Tell students that Jupiter’s four largest moons are the size of small planets. In fact, all are bigger than Pluto and the largest, Ganymede, is bigger than Mercury. Ask, Why isn’t Ganymede called a planet? (It revolves around Jupiter, not the Sun.) Page 10 Saturn • Have students look at the photograph of Saturn on page 10. Read the Saturn Facts and add them to the table. Ask, How are Jupiter and Saturn alike? (huge size, made of gas, lots of moons, length of day) • Read the text on page 10. Then say, Before you read the text, you named some ways in which Jupiter and Saturn are alike. What else do these planets have in • Inform students that until Voyager 2 flew past Uranus in 1986, only five of its moons were known. Ask, Why do you think Uranus’s other moons were not discovered before then? (Students may speculate that the moons are too small and faint to be seen through a telescope.) Uranus’s moons are named after characters from the plays of Shakespeare and a famous poem by Alexander Pope. Other moons in our Solar System are named after characters from Greek mythology. • Students may be interested to know that Uranus was almost named Herschel after the astronomer (William Herschel) who discovered it. However, some astronomers felt that the planet should have a name from classical mythology like the rest. Delta Science Reader—Solar System 477 • Read and record the Neptune Facts. Then read the text about Neptune. Ask, What other planets did Voyager 2 visit? (Jupiter, Saturn, Uranus) • Guide students to compare and contrast the gas giant planets. Ask, Which of the other gas giant planets is most similar to Neptune? (Uranus) How are they alike? (size, length of day, color, made of similar gases, ring system) In what ways are Uranus and Neptune different? (number of moons, length of year, Uranus gives off little heat and rotates in a different direction) • Read the Pluto Facts with students and record them in the table. Ask, How is Pluto different from the other outer planets? (small size, rocky, only one moon) Which planets does Pluto resemble more? (Mercury, Venus, Earth, Mars) Page 13 Other Objects in Our Solar System • Before reading page 13, ask what other objects in the Solar System students know about. Encourage them to share their ideas. • Tell students to read the text on page 13 and look at the photograph of Halley’s comet. You may wish to share with students that comets have been called “dirty snowballs.” Ask, What makes that a good description of a comet? (Comets are made of dust and ice mixed together.) What causes a comet’s long, glowing tail? (The Sun’s heat starts to vaporize the comet, forming its tail. The Sun’s light reflects off the tail.) • Ask, What is the difference between a meteor and a meteorite? (A meteor is a meteoroid that burns when it enters Earth’s atmosphere. A meteorite is part of a meteor that doesn’t burn up completely and hits the ground.) N O S R • Read the text about Pluto. Ask, What fact about Pluto surprises you the most? (Students may mention its position changing with respect to Neptune.) E P The last time Pluto moved inside Neptune’s orbit was in February 1979. Pluto stayed inside Neptune’s orbit until February 1999. Now Pluto is back outside Neptune’s orbit, and it will remain the farthest planet from the Sun until around 2230, when the switch will happen again. R O F • You may wish to share with students that almost a hundred years passed between the discovery of Neptune in 1846 and Pluto’s discovery in 1930. Some scientists have discussed whether Pluto should be called a planet. Because of its relatively small size, unusual orbit, and closeness to the asteroid group known as the Kuiper Belt, Pluto could be considered a dead comet or a large asteroid. However, there are currently no plans to change Pluto’s official status as a planet. 478 broward county hands-on science L A E S U • If necessary, provide help with the pronunciation of asteroids (ASS-tuhroids), meteoroids (MEE-tee-ur-roids), meteor (MEE-tee-ur), and meteorite (MEE-tee-ur-rite). During certain times of the year, we may be able to see more meteors, or “shooting stars.” We call these clusters of activity meteor showers. Meteor showers happen when Earth passes through trails of debris created by comets as they pass by the Sun. The particles of debris fall through Earth’s atmosphere and burn up with a streak of light that we can see. The last part of the year is typically a strong time for meteor showers. The Perseid (late July to mid-August), Leonid (mid-November), and Geminid (mid-December) meteor showers all happen during this time. © Delta Education. Photocopying and distribution prohibited. Page 12 Neptune, Pluto People in Science (page 14) • One famous example of a crater on Earth that is visible today is Meteor Crater near Winslow, Arizona. This huge pit—1.2 kilometers (0.8 miles) wide and over 180 meters (600 feet) deep—is believed to have been made by a meteorite that crashed to Earth about 50,000 years ago. Another example is Chubb Crater in Canada. A 200-meter (820-feet) deep lake fills this 1.4 million-year-old crater. Adriana C. Ocampo, Planetary Geologist • Ask whether students know what a geologist is. If necessary, explain that a geologist is a scientist who studies the Earth and the Earth’s history as shown in its layers of rock. Ask, What do you think a planetary geologist is? (a scientist who studies planets and other objects in our Solar System; sometimes this helps them learn more about Earth and Earth’s history) Did You Know? (page 15) How Telescopes Work • After reading the text on page 14, ask, What is an impact crater? (the hole in the ground made when a meteorite hits the Earth’s surface) How do you think a meteorite impact may have caused the dinosaurs to become extinct? (Accept reasonable responses.) S R R O © Delta Education. Photocopying and distribution prohibited. Further Facts F E P • Hypotheses about how the Chicxulub impact may have caused the extinction of the dinosaurs vary. Some scientists think that gases, debris, and dust may have clouded the Earth, causing changes in Earth’s climate. L A • Have students read page 15 to determine how the two types of telescopes work. Ask, What is the difference between a refracting telescope and a reflecting telescope? (A refracting telescope uses lenses to collect light; a reflecting telescope uses mirrors. A refracting telescope is more powerful than a reflecting telescope of the same size.) How is the way you look through the telescopes different? (You look straight through a refracting telescope; you look into the side of a reflecting telescope.) N O • If necessary, provide help with the pronunciation of Adriana Ocampo (aydree-AHN-na oh-KOMP-oh), geologist (jeeOL-uh-jist), Chicxulub (CHIK-shoo-loob), and Yucatán (you-kuh-TAN). Students may be interested to know that one of the astronauts who walked on the moon, Harrison Schmitt, is a geologist. He collected Moon rocks on the last Apollo mission to the Moon in 1972. E S U • Direct students’ attention to the diagrams of the refracting and reflecting telescopes. Read the labels with students, and call on volunteers to describe what they see. • Ask, How does a telescope help us see more stars than we can see with our eyes alone? (A telescope’s lenses are bigger and can gather more light than our eyes can.) • Earth is constantly being hit by space debris, but most of it burns up before it reaches Earth’s surface. Nevertheless, some space scientists look for, track, and categorize asteroids and comets that may travel near Earth. A scale called the Torino Scale has been developed to describe the potential for collision with a comet or an asteroid. Delta Science Reader—Solar System 479 • Galileo Galilei was the first to apply the telescope to the study of the night sky. Galileo published an account of his explorations with the telescope, Sidereus Nuncius (Starry Messenger), in 1610. • The largest optical telescope in the world is located in Mauna Kea, Hawaii, at the Keck Observatory. The telescope sits on top of a dormant volcano. The telescope is about 8 stories high, and its primary mirror is 10 meters (32.8 feet) across. • Other large telescopes are located in Chile at the Paranal Observatory. When its four 8-meter-mirrored telescopes work together, it is known as the VLT, short for “Very Large Telescope.” • The Hubble Space Telescope is in orbit 579 km (360 miles) above the Earth. It was launched in 1990. Hubble is not affected by conditions in Earth’s atmosphere, such as clouds, pollution, or light from cities, the way telescopes on Earth are affected. It therefore can provide sharp images of distant objects in space. AFTER READING Summarize Complete the KWL chart you began with students before reading by asking them to share the answers to their questions. Call on volunteers to retell each text section. Then have students use the information in the KWL chart and the Planetary Facts table to write brief summary statements. Discuss with students how using the KWL strategy helped them understand and appreciate the book. Encourage them to share any other reading strategies that helped them understand what they read. Direct attention to the fourth column in the chart and ask, What questions do you still have about the Solar System, its planets, and other objects in the Solar System? What would you like to explore further? Record students’ responses. Then ask, Where do you think you might be able to find this information? (Students might mention an encyclopedia, science books, and the Internet.) Encourage students to conduct further research. N O S R R O E P F 480 broward county hands-on science L A E S U © Delta Education. Photocopying and distribution prohibited. Further Facts Review/Assess Writing Links/Critical Thinking Use the questions that follow as the basis for a discussion of the book or for a written or oral assessment. Present the following as writing assignments. 1. What is the Solar System? (the Sun, the planets, and other space objects that move around the Sun) 1. In this book, the planets are divided into two groups, the inner planets and the outer planets. What is another way the planets can be grouped? Explain how the planets in each group are alike. (Students may classify planets according to size or composition, grouping the inner planets and Pluto together. Other possibilities include the length of a planet’s day, the existence of rings, or large and small numbers of moons.) 2. What are the names of the inner planets? (Mercury, Venus, Earth, Mars) How are they alike? (They all have hard, rocky surfaces.) 3. What are the names of the outer planets? (Jupiter, Saturn, Uranus, Neptune, Pluto) Except for Pluto, how are these planets alike? (They are huge balls of glowing gas, have many moons, and have rings.) 4. If you could travel to each planet in the Solar System, which one would take you the longest to reach? Why? (Pluto, because it’s the farthest away from Earth.) © Delta Education. Photocopying and distribution prohibited. R O L A N O S R E P E S U 2. What is the connection between Earth’s axis and the seasons? (Earth’s axis is tilted. Part of Earth points toward the Sun and part of Earth points away from it. As Earth moves around the Sun, some parts of Earth get more direct sunlight than other parts do. This causes the seasons.) Science Journals: You may wish to have students keep all the writing activities related to the Delta Science Reader in their science journals. References and Resources For trade book suggestions and Internet sites, see the References and Resources section of this teacher’s guide. F Delta Science Reader—Solar System 481 R O 482 E P F broward county hands-on science © Delta Education. Photocopying and distribution prohibited. S R N O L A E S U