reading essentials grade 4 answer key -...

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Reading Essentials Grade 4 Answer Key

CHAPTER 1 KINGDOMS OF LIFE

Lesson 1 Living Things and Their Needs

Read a Table: Is It a Living Thing?grow, reproduce, react to changes (p. 3)

Read a Table: Cell PartsPossible answers: cell wall, chloroplast (p. 5)

Quick Check1. water, food, place to live (p. 3)2. cell walls, chloroplasts, chlorophyll (p. 5)3. cell membranes, nucleus, chromosomes, mitochondria, cytoplasm (p. 5)4. no cell walls, no chloroplasts, no chlorophyll (p. 5)5. tissue (p. 6)6. organ (p. 6)7. organ system (p. 6)8. It makes things look bigger. (p. 7)

Lesson 2 Classifying Living Things

Read a Chart: Classifying Organismsancient bacteria, bacteria, protists, animals (p. 9)

Read a Diagram: Naming OrganismsCanis (p. 13)

Quick Check9. A trait is a feature of a living thing. (p. 8)10. ancient bacteria, bacteria, protists, fungi, plants, animals (p. 9)11. genus (p. 11)12. They have cell walls. (p. 12)13. bacteria (p. 12)14. its genus and species (p. 13)

Lesson 3 The Plant Kingdom

Read a Diagram: Photosynthesissunlight, carbon dioxide (p. 18)

Read a Photo: Plants People EatFruit—Possible answers: tomatoes, apples, peppers, pumpkinsVegetable—Possible answers: potatoes, carrots, turnips (p. 21)

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Quick Check15. by their parts, by how they make new plants (p. 15)16. b: Roots (p. 17)17. a: Stems (p. 17)18. through stomata on the bottom of the leaves (p. 19)19. veins (p. 19)20. light, nutrients, water (p. 20)21. Possible answers: building materials, furniture, houses, clothes, medicine (p. 21)

Lesson 4 How Seed Plants Reproduce

Read a Photo: Conifer Seedsthe male pinecone (23)

Read a Diagram: Making Bigger Pumpkinsoffspring 2 (p. 29)

Read a Photoa—daffodil; b—chain plant (p. 31)

Quick Check22. seed (p. 23)23. pollen (p. 23)24. Possible answers: moving pollen, pollination (p. 25) 25. pollination (p. 27)26. Possible answers: color, size, shape (p. 28)27. pollinate (p. 29)28. bulb (p. 31)29. cutting (p. 31)30. runner (p. 31)31. tuber (p. 31)

Chapter 1: Vocabulary Review

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1. b [organism; top row, starting 1st letter at the left] 2. d [seed; top row, starting 10th letter from the left, at a diagonal]3. a [cell; 2nd row, starting 5th letter from the left] 4. h [trait; top row, 14th column, starting at the top]5. c [pollination; 4th row, starting 1st letter at the left]6. i [kingdom; top row, starting 9th letter from the left, at a diagonal] 7. f [ovary; 3rd row, starting 1st letter at the left]8. j [photosynthesis; bottom row; starting 1st letter at the left]

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9. e [fertilization; 8th row, starting first letter at the left] 10. g [reproduction; 7th row, starting 2nd letter from the left]

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1. life cycle2. spore3. tissue4. organism5. germination6. organ 7. Possible answer: germination, seedling adult plant, pollination, fertilization, fruit with seeds, animal eats fruit

SummarizePossible answer: Living things are grouped by their characteristics. Plants have structures that carry out certain jobs. In the leaves, plants use sunlight to make their own food.

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CHAPTER 2 THE ANIMAL KINGDOM

Lesson 1 Animals Without Backbones

Read a Photo: Invertebrate GroupsThey all are invertebrates. (They have no backbones.) (p. 37)

Read a Photo: Before and AfterIt turns red. It rolls up into a ball. (p. 39)

Quick Check1. by symmetry, by backbone or no backbone (p. 37)2. false; Most mollusks live in water. Snails and slugs live on land. (p. 39)3. true (p. 39)4. false; An echinoderm has spiny skin. (p. 39)5. true (p. 39)6. hard (p. 40)7. outside (p. 40)8. c (p. 43)9. a (p. 43)10. b (p. 43)

Lesson 2 Animals with Backbones

Read a Chart: Classes of Vertebratescold-blooded (p. 45)

Read a Photo: Amphibians and Reptilesfrog (p. 46)

Quick Check11. does not (p. 44)12. changes (p. 44)13. birds, mammals (p. 45)14. Possible answer: They spend part of their lives in water. (p. 47)15. Possible answer: Their skin is covered in scales or plates. (p. 47)16. Possible answer: Their feathers are light. (p. 47)17. Females make milk to feed their young. (p. 49)18. warm-blooded (p. 49)19. hair (p. 49)20. water; most other places on Earth (p. 49)

Lesson 3 Systems in Animals

Read a Diagram: Respiratory and Circulatory Systems

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Gills are part of the fish’s respiratory system. Lungs are part of the hamster’s respiratory system. (p. 53)

Read a Diagram: The Digestive Systemto the intestine (p. 54)

Quick Check21. b (p. 51)22. a (p. 51)23. c (p. 51)24. true (p. 53)25. false; the heart is the main organ in the circulatory system. (p. 53)26. digestive system with one opening (p. 55)27. digestive system with two openings (p. 55)28. digestive system with many parts (p. 55)29. digestive system with many parts (p. 55)

Lesson 4 Animal Life Cycles

Read a Photo: Complete MetamorphosisA larva hatches from each egg. (p. 59)

Read a Table: Kinds of Reproductionbudding, regeneration (p. 61)

Quick Check30. chick (p. 57)31. adult (p. 57)32. complete metamorphosis (p. 59)33. heredity (p. 61)34. fertilization (p. 61)35. when an animal changes its behavior by interacting with its environment (or other animals) (p. 63)38. a set of actions that a living thing is born with (p. 63)


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Across2. exoskeleton4. invertebrate5. clone6. muscular system7. respiratory system8. nervous system

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9. cold-blooded

Down1. warm-blooded3. skeletal system

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SummarizePossible answer: All animals are classified as either invertebrate or vertebrate. Invertebrates are animals without backbones. Vertebrates are animals with backbones. Animals have body systems to do basic life functions. Animals go through stages of growth and change during their life cycles.

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CHAPTER 3 EXPLORING ECOSYSTEMS

Lesson 1 Introduction to Ecosystems

Read a Diagram: A Pond EcosystemPossible answers: The fish live in the water. The duck lives on the land in a nest. The turtle lives in the water and on land. (p. 69)

Read a Photo: Populations and CommunitiesLeft picture: ferns, parrots; Right picture: bears, grasses (p. 71)

Quick Check1. c (p. 69)2. d (p. 69)3. a (p. 69)4. b (p. 69)5. A community is all the populations in an ecosystem. (p. 71)6. A population is all the members of a species that live in an ecosystem. (p. 71)

Lesson 2 Biomes

Read a Map: Biomes of the World deciduous forest, grassland (p. 73)

Read a Photo: Tree Orchidsin the understory (p. 75)

Quick Check7. Possible answer: taiga, grassland, tropical rain forest, tundra, deciduous forest, desert (p. 73)8. Possible answer: taiga, grassland, tropical rain forest, tundra, deciduous forest, desert (p. 73)9. Decidous Forest: cool to moderate; Tropical Rain Forest: warm (p. 75)10. Deciduous Forest: fertile; Tropical Rain Forest: poor in nutrients (p. 75)11. desert (p. 76)12. Possible answers: freshwater, wetland, estuary, ocean.(p. 77)13. Possible answers: freshwater, wetland, estuary, ocean.(p. 77)14. Possible answers: freshwater, wetland, estuary, ocean.(p. 77)15. Possible answers: freshwater, wetland, estuary, ocean.(p. 77)

Lesson 3 Relationships in Ecosystems

Read a Diagram: Pond Food Chainsunfish (p. 80)

Read a Diagram: Ocean Food Web

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Possible answer: The whale is a predator of seal, seagulls, and fish. (p. 82)

Quick Check16. depend on other living things for food and energy (p. 79)17. break down wastes and remains of other living things (p. 79)18. algae (p. 81)19. All of the living things in the food chain will become food for decomposers. (p. 81)20. energy pyramid (p. 83)


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1. grassland2. biotic factor3. consumer4. desert5. energy pyramid6. habitat7. decomposer

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Across2. prey3. producer4. taiga5. competition6. predator7. tundra

Down1. ecosystem3. population

SummarizePossible answer: Living and nonliving things interact with each other in an ecosystem. Earth has six major biomes, or large ecosystems. Each biome has its own kind of plants, animals, weather, and soil. Energy is passed from one living thing to another in an ecosystem.

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CHAPTER 4 SURVIVING IN ECOSYSTEMS

Lesson 1 Animal Adaptations

Read a Photo: Animal Adaptationsfennec fox (p. 89)

Read a Photo: Animal InteractionsThe fish eat algae off the turtle’s shell. (p. 91)

Quick Check1. adaptations (p. 89)2. c (p. 91)3. b (p. 91)4. a (p. 91)

Lesson 2 Plants and Their Surroundings

Read a Diagram: Tropism Experimentstems (p. 92)

Read a Photo: Desert Adaptationswaxy cover (p. 93)

Quick Check5. tropism (p. 92)6. It has a thick, waxy cover (p. 93)

Lesson 3 Changes in Ecosystems

Read a Photo: Natural Change in EcosystemsPlants and trees grew. (p. 94)

Read a Photo: Manufactured EcosystemsThey can provide a home for living things. (p. 97)

Quick Check7. volcanic eruption (p. 95)8. destroyed coastal wetlands (p. 95)9. landslide, flood (p. 95)10. too little rain; drought (p. 95)11. Possible answers: deforestation, overpopulation, pollution (p. 97)12. Possible answers: deforestation, overpopulation, pollution (p. 97)13. Possible answers: deforestation, overpopulation, pollution (p. 97)14. extinct (p. 98)15. accommodation (p. 98)

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16. endangered (p. 98)17. endangered (p. 98)


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1. b2. c3. a4. d5. d6. a

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1. e2. a3. b4. g5. f6. d7. c

Summarize Possible answer: Animals have adaptations that help them live in their environments. Plants also adapt and respond to their environments. When an ecosystem changes, some animals survive, but others die.

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CHAPTER 5 SHAPING EARTH

Lesson 1 Earth

Read a Map: Landforms of the United States1: mountains; 2: canyon; 3: plains; 4: sand dunes (p. 105)

Read a Diagram: From Land to Seacontinental slope (p. 107)

Quick Check1. d (p. 104)2. a (p. 104)3. c (p. 104)4. b (p. 104)5. A delta is a landform that is formed where a river meets the ocean. (p. 107)6. Possible answers: solid, place where landforms are located (p. 109)7. Possible answers: hot, made of iron, at center of Earth (p. 109)

Lesson 2 The Moving Crust

Read a Diagram: Mountains in the Makingboth of them (fault-block and fold mountains) (p. 111)

Read a Diagram: Time Line of Seismic Study1937 (p. 115)

Quick Check8. fault (p. 111)9. fold (p. 111)10. An earthquake is a sudden shaking of Earth’s crust caused by movement along a fault. (p. 113)11. seismic waves (p. 115)12. seismograph (p. 115)13. a place where Earth’s crust is very thin and volcanoes form (p. 117)

Lesson 3 Weathering and Erosion

Read a Photo: Rivers Shape the Landthe movement of river water (p. 121)

Read a Diagram: A Glacier Deposits Landat the terminus (p. 123)

Quick Check

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14. weathering that changes the size and shape of rocks without changing what the rocks are made of (p. 119)15. weathering that changes rocks by changing what the rocks are made of (p. 119)16. erosion (p. 121)17. deposition (p. 121)18. A glacier is a thick, moving sheet of ice. (p. 123)19. Possible answers: mining, landfills, cutting down forests (p. 125)20. Possible answers: mining, landfills, cutting down forests (p. 125)21. Possible answers: mining, landfills, cutting down forests (p. 125)

Lesson 4 Changes Caused by the Weather

Read a Photo: Before and AfterPossible answer: The fire burned down trees and harmed animals. Possible answer: The flood covered the plaza so people could not walk there. (p. 127)

Read a Photo: Hurricane DamagePossible answer: It destroyed houses. (p. 129)

Quick Check22. After a flood, new soil is put on the land. The nutrients in the soil help plants grow. (p. 126)23. Possible answers: lightning; people playing with matches (p. 126)24. tornado (p. 128)25. hurricane (p. 128)26. Possible answers: in places with mountains or hills, in high places where precipitation has occurred (p. 131)


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1. e2. f3. d4. a5. b6. h7. c8. g9. crust10. hurricane

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Across2. weathering6. landslide7. flood8. deposition9. tornado10. mantle

Down1. seismic wave3. volcano4. outer core5. mountain

SummarizePossible answer: Landforms cover Earth’s crust. Earth is made up of layers. Earth’s surface is broken into large plates that move slowly. Many landforms form at the plate edges. Weathering, erosion, and deposition are slow processes that shape the land. Floods, fires, and landslides can change the land quickly.

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CHAPTER 6 SAVING EARTH’S RESOURCES

Lesson 1 Minerals and Rocks

Read a Table: Moh’s Hardness Scalediamond (p. 137)

Read a Diagram: The Rock Cycleigneous rock (p. 144)

Quick Check1. the hardness of minerals (p. 137)2. igneous rocks (p. 139)3. sedimentary rocks (p. 139)4. metamorphic rock (p. 141)5. Possible answers: floors, tiles, buildings (p. 143)6. Possible answers: bricks, chalk (p. 143)

Lesson 2 Soil

Read a Diagram: Weathering Caused by Living ThingsThe rabbit moved pieces of sediment and mixed them around to dig the hole. (p. 144)

Read a Photo: Permeability of Soilscoarse soil (p. 146)

Quick Check7. soil horizons (layers) (p. 145)8. Rock (such as bedrock) and humus differ from place to place. (p. 145) 9. spaces between particles of soil (p. 147)10. how fast water passes through something (p. 147)11. Possible answers: Topsoil is home to many living things. Topsoil is needed for growing crops. (p. 149)12. sandy soil, which is very porous soil (p. 149)13. medium-textured soils (p. 149)

Lesson 3 Resources from the Past

Read a Diagram: How Coal FormsThe rock layer is pressed into soft coal. (p. 153)

Read a Chart: Sources of Electricitycoal (p. 155)

Quick Check

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14. imprint (p. 150)15. measuring Earth’s history in millions and even billions of years (p. 151)16. an energy source that formed millions of years ago (p. 153)17. a useful material that cannot be replaced easily (p. 153)18. False; A renewable resource is a useful material that can be replaced. (p. 155) 19. True (p. 155)20. True (p. 155)

Lesson 4 Water

Read a Map: From Lake to OceanSt. Lawrence River (p. 157)

Read a Diagram: Water TreatmentIt goes into the settling basin. (p. 159)

Quick Check21. False; Ocean water contains salt. (p. 157)22. True (p. 157)23. False; Groundwater is stored in cracks and spaces under the ground. (p. 157)24. reservoirs, groundwater (p. 159)25. to kill harmful organisms (p. 159)26. Possible answers: irrigation, boating, electricity (p. 161)27. Possible answers: irrigation, boating, electricity (p. 161)28. Possible answers: irrigation, boating, electricity (p. 161)

Lesson 5 Pollution and Conservation

Read a Photo: Contour PlowingThe farmers have used contour plowing, a form of plowing used on sloping lands. (p. 164)

Read a Photo: The 3 Rs in ActionRecycling (p. 165)

Quick Check 29. Pollution is putting a harmful substance into an environment. (p. 163)30. Smog makes the air hard to breathe. (p. 163)31. Possible answer: Litter can pollute the land. (p. 163)32. conservation (p. 164)33. reduce; accept all reasonable responses (p. 165)34. reuse; accept all reasonable responses (p. 165)35. recycle; accept all reasonable responses (p. 165)

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1. a2. d3. d4. c5. c6. a7. b8. b

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1. d2. g3. a4. e5. k6. h7. i8. f9. b10. c11. j12. reduce, reuse, recycle

SummarizePossible answer: Rocks are made of minerals. Rocks change and form. Soil is made of weathered rock and other materials. Soil forms slowly in layers. Fossils give us clues about Earth's history. Some of our fuels come from fossils. Water collects on and below Earth's surface. It is stored and used in different ways. People pollute the land, water, and air. We can protect our resources with conservation.

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CHAPTER 7 WEATHER AND CLIMATE

Lesson 1 Air and Weather

Read a Diagram: Layers of Earth’s Atmospheretroposphere (p. 171)

Read a Photo: Humidity in a Rain ForestPossible answers: Plants grow well there and you can almost see the water vapor in the air. (p. 172)

Quick Check1. nitrogen (p. 171)2. Possible answers: air temperature, humidity, air pressure, precipitation (p. 173)3. Possible answers: air temperature, humidity, air pressure, precipitation (p. 173)4. Possible answers: air temperature, humidity, air pressure, precipitation (p. 173)5. Possible answers: air temperature, humidity, air pressure, precipitation (p. 173)6. e (p. 175)7. f (p. 175)8. b (p. 175)9. a (p. 175)10. c (p. 175)11. d (p. 175)

Lesson 2 The Water Cycle

Read a Diagram: The Water Cyclecondensation (p. 179)

Read a Diagram: Many Types of Cloudscirrocumulus (p. 181)

Quick Check12. evaporation (p. 177)13. condensation (p. 177)14. precipitation (p. 177)15. water cycle (p. 179)16. a (p. 181)17. freeze (p. 183)

Lesson 3 Tracking the Weather

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Read a Diagram: Different Frontsabove the cold air mass (p. 185)

Read a Map: U.S. Weather mapsunny, 70s (p. 186)

Quick Check18. warm front (p. 185)19. cold front (p. 185)20. stationary front (p. 185)21. Possible answers: air temperature, air pressure, precipitation, wind, the locations of fronts (p. 187)22. stay away from water and trees (p. 189)23. head for a sturdy shelter (p. 189)24. move inland (p. 189)

Lesson 4 Climate

Read a Map: Ocean Currentswarm currents (p. 192)

Read a Photo: The Mountain Effectat the top or peak (p. 194)

Quick Check25. the average weather pattern of a region over time (p. 191)26. True (p. 193)27. False; Climates near the equator are warm and rainy. (p. 193)28. False; Water heats more slowly than land. (p. 193)29. The air cools. Water vapor in the air condenses. Clouds form. Precipitation forms and falls. (p. 195)


Page 1961. temperature 2. air pressure 3. thermometer 4. evaporation 5. water vapor6. atmosphere7. cold front

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1. j

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2. d3. b4. i5. g6. a7. c8. f9. h10. e

SummarizePossible answer: Scientists measure properties in Earth’s atmosphere to tell about weather. The water cycle shows how water changes between Earth and the air. We can predict weather by looking at air masses and fronts. Climate is a pattern of weather in a place.

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CHAPTER 8 THE SOLAR SYSTEM AND BEYOND

Lesson 1 Earth and Sun

Read a Diagram: Earth’s Rotationthe direction Earth rotates (p. 200)

Read a Diagram: Earth’s RevolutionWinter (p. 203)

Quick Check1. Night begins. (p. 201)2. A part of Earth faces the Sun. (p. 201)3. A shadow forms. (p. 201)4. revolution (p. 203)5. orbit (p. 203)6. a (p. 205)7. b (p. 205)

Lesson 2 Earth and Moon

Read a Diagram: Phases of the Moonwaxing gibbous moon (p. 209)

Read a Diagram: Two Kinds of Eclipsesbetween Earth and the Sun (p. 210)

Quick Check8. a hollow area or pit in the ground (p. 207)9. Moon (p. 208)10. orbit (p. 208)11. phases (p. 208)12. full moon (p. 208)13. on the Moon (p. 211)14. on Earth (p. 211)

Lesson 3 The Solar System

Read a Diagram: The Solar SystemNeptune (p. 213)

Read a Photo: New and Old TelescopesPossible answers: size; technology; shape; one uses light, the other uses radio waves (p. 214)

Quick Check

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15. a round object in space that is a satellite of the Sun (p. 213)16. a force of attraction between all objects (p. 213)17. Possible answers: satellites, probes, space shuttles, rockets, space station, telescopes (p. 215)18. Possible answers: satellites, probes, space shuttles, rockets, space station, telescopes (p. 215)19. Possible answers: satellites, probes, space shuttles, rockets, space station, telescopes (p. 215)20. Mercury (p. 217)21. Venus (p. 217)22. Earth (p. 217)23. Mars (p. 217)24. Neptune (p. 219)25. Saturn (p. 219)26. Uranus (p. 219)27. Jupiter (p. 219)28. Possible answers: meteoroid, comet, asteroids29. Possible answers: meteoroid, comet, asteroids30. Possible answers: meteoroid, comet, asteroids

Lesson 4 Stars and Constellations

Read a Diagram: Nearest Stars to Earth9.5 (p. 222)

Read a Diagram: ConstellationsPisces, Aquila (p. 224)

Quick Check31. True (p. 223)32. False; Galaxies are large groups of stars. (p. 223)33. a group of stars that seem to make a pattern or picture in the sky (p. 225)34. Possible answer: to know when to plant crops (p. 225)35. True (p. 227)36. False; You do need to use sunscreen on a cloudy day because the Sun can give you a sunburn on a cloudy day. (p. 227)37. True (p. 227)


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Across1. crater3. revolution4. rotation

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5. lunar eclipse8. planet

Down1. constellation2. solar eclipse6. axis7. star

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1. telescope2. gravity3. constellation4. comet5. phase6. planet7. rotation8. solar system

SummarizePossible answer: Earth’s movement through space causes day, night, and the seasons. As the Moon revolves around Earth, we see its phases. The Sun is the center of the solar system. Planets, moons, and other objects orbit the Sun. Stars are spheres of hot gases that give off light and heat energy. The Sun is a star.

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CHAPTER 9 PROPERTIES OF MATTER

Lesson 1 Describing Matter

Read a Photo: Comparing MassesThe rock has more mass because that side of the balance is lower. (p. 232)

Read a Photo: Uses of Matterobjects made by people; objects in nature (p. 235)

Quick Check1. mass (p. 233)2. matter (p. 233)3. property (p. 233)4. juice5. air6. log7. True8. True9. True10. False

Lesson 2 Measurement

Read a Table: Metric UnitsA kilometer is longer than a meter. (p. 236)

Read a Diagram: DensityThe air particles inside the balloon are farther apart. Also, the balloon is floating in the air. (p. 238)

Quick Check11. a (p. 237)12. c (p. 237)13. b (p. 237)14. true (p. 239)15. true (p. 239)16. false (p. 239)17. A rock will weigh less on the moon because the Moon has a weaker pull of gravity. (p. 241)

Lesson 3 Classifying Matter

Read a Table: Periodic Table of the ElementsThere are more metals on the periodic table. (p. 245)

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Read a Diagram: Properties of ElementsSodium will react with nonmetals because it is in the same column as potassium. Elements in this column react with nonmetals. (p. 247)

Quick Check18. metal (p. 243)19. nonmetal (p. 243)20. metalloid (p. 243)21. nonmetal (p. 245)22. metalloid (p. 245)23. nonmetal (p. 245)24. nonmetal (p. 245)25. metalloid (p. 245)26. metal (p. 245)27. iron (Fe), cobalt, (Co), nickel (Ni) (p. 247)28. They are in the same row. (p. 247)


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1. b2. a3. c4. b5. a6. c7. d8. d

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1. matter 2. element 3. periodic table 4. mass 5. length 6. metal

SummarizePossible answer: Anything that has mass and takes up space is matter. Matter can be described by properties such as mass, volume, and state. Matter can be measured. All matter is made of elements. The elements are organized in a periodic table.

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CHAPTER 10 MATTER AND ITS CHANGES

Lesson 1 How Matter Can Change

Read a Diagram: How Water Changes StateThe particles move faster because energy is added. (p. 255)

Read a Diagram: Reaction of Iron and Sulfurheat from the rod (p. 257)

Quick Check1. a physical change in the clay’s shape (p. 253)2. a change in state from a solid to a liquid (p. 253)3. liquid (p. 255)4. gas (p. 255)5. liquid (p. 255)6. – 8. Chemical Changes: toasting a marshmallow, rusting iron, fizzing bubbles (p. 257)9. – 11. Physical Changes: cutting paper, melting ice, bending clay (p. 257)12. Chemical change—Possible answer: Bread dough is baked in an oven. It turns hard and crusty. (p. 259)Physical change—Possible answer: Bread dough can be pushed, pulled, stretched, and shaped into rolls. (p. 259)

Lesson 2 Mixtures

Read a Photo: Kinds of Mixturessolids and a liquid (p. 260)

Read a Photo: Natural SettlingSettling (p. 262)

Quick Check13. true (p. 261)14. true (p. 261)15. false (p. 261)16. magnet (p. 262)17. filter (p. 262)18. distillation, evaporation (p. 263)

Lesson 3 Compounds

Read a Diagram: Combining Elementshydrogen and oxygen (p. 265)

Read a Diagram: Acids and Bases

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lemons (p. 267)

Quick Check19. chemically (p. 264)20. no (p. 264)21. It turns red. (p. 267)22. It turns blue. (p. 267)


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1. c2. a3. b4. d5. c6. d7. b8. c

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1. change of state2. chemical3. mixture4. solution5. compound6. A change of state is a physical change because the matter does not change its chemical properties. Water remains water whether it is in a solid, liquid, or gas state.

SummarizePossible answer: Physical changes start and end with the same kind of matter. A change of state is a physical change. A chemical change forms a new kind of matter. Matter can be physically combined into mixtures and solutions. Compounds are formed by chemical changes between two or more elements.

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CHAPTER 11 FORCES

Lesson 1 Motion and Forces

Read a Photo: AccelerationYes, the skaters are accelerating because any change in direction is acceleration. (p. 274)

Read a Diagram: The Effect of GravityGravity (p. 277)

Quick Check1. speed (p. 273)2. position (p. 273)3. direction (p. 273)4. The surface of the table rubs against the surface of the ball. This rubbing slows the ball and can stop the ball’s motion. (p. 275)5. false (p. 277)6. true (p. 277)7. false (p. 277)8. true (p. 277)

Lesson 2 Changing Motion

Read a Diagram: Newtons of Force20 N (p. 279)

Read a Diagram: Force and AccelerationThe same amount of force is applied in both drawings. (p. 280)

Quick Check9. Balanced Force (p. 279)10. Unbalanced Force (p. 279)11. Unbalanced Force (p. 279)12. Balanced Force (p. 279)13. increases (p. 281)14. decreases (p. 281)15. more (p. 281)16. true (p. 283)17. true (p. 283)18. false (p. 283)

Lesson 3 Work and Energy

Read a Diagram: Forces at WorkGravity (p. 285)

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Read a Diagram: Transforming EnergySolar panels transform light energy into electrical energy. Lamps transform electrical energy into light energy. (p. 289)

Quick Check19. Potential energy is the future ability to do work. Kinetic energy is the energy of motion.20. nuclear energy (p. 287)21. thermal energy (p. 287)22. mechanical energy (p. 287)23. light energy (p. 287)24. electrical energy (p. 287)25. chemical energy (p. 287)26. transforms (p. 289)28. transfers (p. 289)

Lesson 4 Simple Machines

Read a Diagram: Types of Pulleysthe fixed pulley (p. 293)

Read a Photo: Three Simple MachinesThey all have inclined planes. (p. 294)

Quick Check28. false (p. 291)29. true (p. 291)30. true (p. 291)31. false (p. 291)32. wheel and axle (p. 293)33. pulley (p. 293)34. movable (p. 293)35. wedge (p. 294)37. inclined plane (p. 294)37. lever, wheel and axle, screw (p. 295)


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1. force 2. gravity 3. energy 4. machine 5. speed

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6. work

7

1. d2. b3. a4. c5. a6. d

SummarizePossible answer: Motion occurs when an object changes its position. Many forces, such as friction and gravity, can change motion. Unbalanced forces cause a change in motion. Work is done when a force is used to move an object a certain distance. Energy is the ability to do work. Simple machines help us to do work.

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CHAPTER 12 ENERGY

Lesson 1 Heat

Read a Photo: Measuring TemperatureNo, the water will not freeze because water freezes at 0°C and 32°F. (p. 301)

Read a Diagram: Heat TransferWarmer particles rise to the top. (p. 302)

Quick Check1. begin to slow down (p. 301)2. begin to speed up (p. 301)3. conduction (p. 303)4. convection (p. 303)5. radiation (p. 303)6. faster (p. 305)7. expands (p. 305)8. shrinks (p. 305)9. burn (p. 305)10. heat (p. 305)

Lesson 2 Sound

Read a Diagram: Sound SpeedsSound travels faster in iron. (p. 308)

Read a Diagram: Comparing Sound Wavesthe wave with the high amplitude (second from the top) (p. 310)

Quick Check11. vibration (p. 307)12. sound wave (p. 307)13. Dolphins use echoes to find prey. Fish and other objects reflect the sound waves made by dolphins. (p. 309)14. wavelength (p. 310)15. frequency (p. 310)16. false (p. 311)17. false (p. 311)18. true (p. 311)

Lesson 3 Light

Read a Diagram: Wavelengths of Lightgreen (p. 313)

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Read a Diagram: How the Eye Worksthe cornea (p. 315)

Quick Check19. gamma (p. 313)20. visible spectrum (p. 313)21. Glasses that help you see far away are made with concave lenses. (p. 315)22. Reading glasses make objects seem bigger because they are made with convex lenses. (p. 315)23. Refraction happens when light rays are bent. (p. 315)24. green light (p. 316)25. transparent (p. 317)26. translucent (p. 317)27. opaque (p. 317)

Lesson 4 Electricity

Read a Diagram: Open and Closed CircuitsThe circuit is closed. (p. 321)

Read a Diagram: Series and Parallel Circuitsa parallel circuit (p. 323)

Quick Check28. Rubbing the balloon with a wool cloth causes a buildup of negative charges. (p. 319)29. Balloon 3 has a negative charge. (p. 319)30. Balloon 4 is neutral. (p. 319)31. Balloons 2 and 3 have static electricity. (p. 319)32. circuit (p. 321)33. current electricity (p. 321)34. because when one light is turned off, other lights and appliances can stay on (p. 323)35. false (p. 325)36. true (p. 325)37. true (p. 325)

Lesson 5 Magnetism and Electricity

Read a Diagram: How an Electric Motor WorksThe magnetic force causes the loop and shaft to spin. (p. 329)

Read a Diagram: How a Generator Worksthe turbine (p. 331)

Quick Check

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38. attract (p. 326)39. repel (p. 326)40. false (p. 327)41. true (p. 327)42. true (p. 327)43. 3 (p. 329)44. 2 (p. 329)45. 1 (p. 329)46. A generator changes mechanical energy into electrical energy. A motor changes electrical energy into mechanical energy. (p. 331)47. power plant (p. 333)48. step-down (p. 333)49. power lines (p. 333)


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1. b2. a3. a4. c5. b6. d7. b8. c

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1. heat2. echo3. pitch4. reflection5. circuit6. radiation7. wavelength8. sound wave

SummarizePossible answer: Heat flows from warmer to cooler objects. Heat is transferred by conduction, convection, and radiation. All sounds begin with a vibration. Sound travels in waves. Light is made up of waves with different wavelengths. Light waves travel in a straight line. Static electricity is a buildup of charges. Current electricity flows through a circuit. Magnets can attract and repel. Electromagnets use electric current.

reading essentials grade 4 answer key -...

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