1. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Formation of the Solar System Section 1 A Solar System Is Born Section 2 The Sun: Our Very Own Star Section 3 The Earth Takes Shape Section 4 Planetary Motion Chapter 20 Table of Contents

2. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 Bellringer How our Solar System was Made In your science journal, describe how you think our solar system was formed. Your entry should be at least 5 sentences long and be neat. Use a lot of detail to support your answer. Section 1 A Solar System Is Born On your desk… -Writing Utensil -Homework (The Big Bang Theory Questions) -Science Journal

3. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 How did the solar system form? What part did gravity play in the formation of the solar system? Essential Question Section 1 A Solar System Is Born

4. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 Watch and Think… If you drop a heavy object, will it fall faster than a lighter one? According to the law of gravity, the answer is no. In 1971, Apollo 15 astronaut David Scott stood on the moon and dropped a feather and a hammer. Television audiences were amazed to see both objects strike the moon’s surface at the same time. Now, you can perform a similar experiment. Section 1 A Solar System Is Born

5. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 Experiment Section 1 A Solar System Is Born Materials: -2 pieces of identical notebook paper -Book Procedure: 1.Crumple 1 piece of notebook paper into a ball. 2.Place the flat paper on top of the book. Place the paper ball on top of the flat paper. 3.Hold the book waist high, and then drop it to the floor.

6. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 Experiment Results Section 1 A Solar System Is Born Analysis 1.Which piece of paper reached the bottom first? 2.Did either piece of paper fall slower than the book? Explain. 3.Now, hold the ball and flat paper in different hands. Drop both pieces of paper at the same time. Besides gravity, what affected the speed of the falling paper?

7. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 Watch this Brain Pop clip on gravity. Take the quiz together and keep in your science folder to study. Gravity Section 1 A Solar System Is Born

8. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 Watch this video clip on how the solar system was formed. Fill in your class connection and questions sheet s we watch the presentation for any of the columns you would like. Then, fill in the graphic organizer as you watch the power point The Formation of the Solar System Section 1 A Solar System Is Born

9. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 Nebula Long ago, gravity made gas and dust from a nebula attract each other. A nebula is a cloud of gas and dust in space. The gas and dust swirled around the nebula and eventually flattened into a rotating disk. Section 1 A Solar System Is Born

10. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 Formation of Planets As bits of dust circled the center of the solar nebula, some collided and stuck together to form golf ball- sized bodies. Section 1 A Solar System Is Born As more collisions happened, the bodies continued to grow and eventually became the planets.

11. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 Outer Planets Gas Giants The largest planets formed near the outside of the solar system, where hydrogen and helium were located. Section 1 A Solar System Is Born These outer planets grew to huge sizes and became the gas giants: Jupiter, Saturn, Uranus, and Neptune.

12. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 Inner Planets Closer to the center of the solar system, where Mercury, Venus, Earth, and Mars formed, temperatures were too hot for gases to remain. Therefore, the inner planets in our solar system are made of mostly rocky material. Section 1 A Solar System Is Born

13. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 The Birth of a Star As the planets were forming, other matter was traveling toward the center. Eventually the gasses that collected in the center of the solar system reacted and our sun was born. Section 1 A Solar System Is Born

14. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 How Long Did it Take? It took about 10 million years for our solar system to form. Section 1 A Solar System Is Born

15. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 Write or Draw Using your graphic organizer and the presentation from today, write or draw a story on how the solar system was formed. You will be sharing your work next class. I will also be collecting your work for a grade. Section 1 A Solar System Is Born

16. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 Bellringer Can You Land on the Sun? Could astronauts land on a star in the same way that they landed on the moon? Explain why or why not in your science journal. Then, explain why the sun is important to Earth. Your journal entry should be neat and at least 5 sentences long. Section 2 The Sun: Our Very Own Star On your desk… -Writing Utensil -Science Journal -Homework (Picture/Story about formation of the solar system)

17. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 Share your work with your group. Everyone must have a turn Your turn should not last longer than 2 minutes. All group members will be respectful of others. Story or picture of the formation of the solar system Section 2 The Sun: Our Very Own Star When you are done Turn in your work Return to your seat quietly

18. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 Why is the sun important to life on Earth? How far away is the sun from Earth? Essential Questions Section 2 The Sun: Our Very Own Star

19. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 The Structure of the Sun The sun is basically a large ball of gas made mostly of hydrogen and helium held together by gravity. Although the sun may appear to have a solid surface, it does not. The visible surface of the sun starts at the point where the gas becomes so thick that you cannot see through it. The sun has been shining on the Earth for about 4.6 billion years. Section 2 The Sun: Our Very Own Star

20. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 The Sun Section 2 The Sun: Our Very Own Star Click below to watch the Brain Pop Video on the Sun. Brain Pop

21. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 How far is the Sun from the Earth? Section 2 The Sun: Our Very Own Star Today, you will be completing a lab to find out just how far away the Sun is from the Earth. This lab uses similar triangles to calculate the distance!

22. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Bellringer The Earth is approximately 4.6 billion years old. The first fossil evidence of life on Earth has been dated between 3.7 billion and 3.4 billion year ago. Write a paragraph in your science journal describing what Earth might have been like during the first billion years of its existence. Chapter 20 Section 3 The Earth Takes Shape

23. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 Describe the formation of the solid Earth. Describe the structure of the Earth. Explain the development of Earth’s atmosphere and the influence of early life on the atmosphere. Describe how the Earth’s oceans and continents formed. Objectives Section 3 The Earth Takes Shape

24. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 The Earth is mostly made of rock. Nearly three-fourths of its surface is covered with water. Our planet is surrounded by a protective atmosphere of mostly nitrogen and oxygen, and smaller amounts of other gases. Formation of the Solid Earth Section 3 The Earth Takes Shape

25. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 The Earth formed as planetesimals in the solar system collided and combined. From what scientists can tell, the Earth formed within the first 10 million years of the collapse of the solar nebula. Formation of the Solid Earth, continued Section 3 The Earth Takes Shape

26. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 The Effects of Gravity When a young planet is still small, it can have an irregular shape. As the planet gains more matter, the force of gravity increases. When a rocky planet, such as Earth, reaches a diameter of about 350 km, the force of gravity becomes greater than the strength of the rock. As the Earth grew to this size, the rock at its center was crushed by gravity and the planet started to become round. Formation of the Solid Earth, continued Section 3 The Earth Takes Shape

27. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 The Effects of Heat As the Earth was changing shape, it was also heating up. As planetesimals continued to collide with the Earth, the energy of their motion heated the planet. Radioactive material, which was present in the Earth as it formed, also heated the young planet. Formation of the Solid Earth, continued Section 3 The Earth Takes Shape

28. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 After Earth reached a certain size, the temperature rose faster than the interior could cool, and the rocky material inside began to melt. Today, the Earth is still cooling from the energy that was generated when it formed. Volcanoes, earthquakes, and hot springs are effects of this energy trapped inside the Earth. Formation of the Solid Earth, continued Section 3 The Earth Takes Shape

29. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 As the Earth’s layers formed, denser materials, such as nickel and iron, sank to the center of the Earth and formed the core. Less dense materials floated to the surface and became the crust. This process is shown on the next slide. How the Earth’s Layers Formed Section 3 The Earth Takes Shape

30. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 Section 3 The Earth Takes Shape

31. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 The crust is the thin and solid outermost layer of the Earth above the mantle. It is 5 to 100 km thick. Crustal rock is made of materials that have low densities, such as oxygen, silicon, and aluminum. How the Earth’s Layers Formed, continued Section 3 The Earth Takes Shape

32. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 The mantle is the layer of rock between the Earth’s crust and core. It extends 2,900 km below the surface. Mantel rock is made of materials such as magnesium and iron. It is denser than crustal rock. How the Earth’s Layers Formed, continued Section 3 The Earth Takes Shape

33. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 The core is the central part of the Earth below the mantle. It contains the densest materials, including nickel and iron. The core extends to the center of the Earth—almost 6,400 km below the surface. How the Earth’s Layers Formed, continued Section 3 The Earth Takes Shape

34. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 Earth’s Early Atmosphere Scientists think that the Earth’s early atmosphere was a mixture of gases that were released as the Earth cooled. During the final stages of the Earth’s formation, its surface was very hot—even molten in places. The molten rock released large amounts of carbon dioxide and water vapor. Formation of the Earth’s Atmosphere Section 3 The Earth Takes Shape

35. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 Earth’s Changing Atmosphere As the Earth cooled and its layers formed, the atmosphere changed again. This atmosphere probably formed from volcanic gases. Volcanoes released chlorine, nitrogen, and sulfur, in addition to large amounts of carbon dioxide and water vapor. Some of this water vapor may have condensed to form the Earth’s first oceans. Formation of Earth’s Atmosphere, continued Section 3 The Earth Takes Shape

36. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 Comets, which are planetesimals made of ice, may have contributed to this change of Earth’s atmosphere. As they crashed into the Earth, comets brought in a range of elements, such as carbon, hydrogen, oxygen, and nitrogen. Comets also may have brought some of the water that helped form the oceans. Formation of Earth’s Atmosphere, continued Section 3 The Earth Takes Shape

37. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 Ultraviolet Radiation Scientists think that ultraviolet (UV) radiation helped produce the conditions necessary for life. UV light has a lot of energy and can break apart molecules. Earth’s early atmosphere probably did not have the protection of the ozone layer that now shields our planet from most of the sun’s UV rays. So many of the molecules in the air and at the surface were broken apart by UV radiation. The Role of Life Section 3 The Earth Takes Shape

38. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 Over time, broken down molecular material collected in the Earth’s waters, which offered protection from UV radiation. In these sheltered pools of water, chemicals may have combined to form the complex molecules that made life possible. The first life-forms were very simple and did not need oxygen to live. The Role of Life, continued Section 3 The Earth Takes Shape

39. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 The Source of Oxygen Sometime before 3.4 billion years ago, organisms that produced food by photo- synthesis appeared. Photosynthesis is the process of absorbing energy from the sun and carbon dioxide from the atmosphere to make food. During the process of making food, these organisms released oxygen—a gas that was not abundant in the atmosphere at the time. The Role of Life, continued Section 3 The Earth Takes Shape

40. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 Photosynthetic organisms played a major role in changing Earth’s atmosphere to become the mixture of gases it is today. Over the next hundreds of millions of years, more oxygen was added to the atmosphere while carbon dioxide was removed. The Role of Life, continued Section 3 The Earth Takes Shape

41. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 As oxygen levels increased, some of the oxygen formed a layer of ozone in the upper atmosphere. The ozone blocked most of the UV radiation and made it possible for life, in the form of simple plants, to move onto land about 2.2 billion years ago. The Role of Life, continued Section 3 The Earth Takes Shape

42. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 Scientists think that the oceans probably formed during Earth’s second atmosphere, when the Earth was cool enough for rain to fall and remain on the surface. After millions of years of rainfall, water began to cover the Earth. By 4 billion years ago, a global ocean covered the planet. Formation of Oceans and Continents Section 3 The Earth Takes Shape

43. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 Ocean Formation Section 3 The Earth Takes Shape Click below to watch the Visual Concept. You may stop the video at any time by pressing the Esc key. Visual Concept

44. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 The Growth of Continents After a while, some of the rocks were light enough to pile up on the surface. These rocks were the beginning of the earliest continents. The continents gradually thickened and slowly rose above the surface of the ocean. These continents did not stay in the same place, as the slow transfer of thermal energy in the mantle pushed them around. Oceans and Continents, continued Section 3 The Earth Takes Shape

45. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 About 2.5 billion years ago, continents really started to grow. By 1.5 billion years ago, the upper mantle had cooled and had become denser and heavier. At this time, it was easier for the cooler parts of the mantle to sink. These conditions made it easier for the continents to move in the same way they do today. Oceans and Continents, continued Section 3 The Earth Takes Shape

46. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 4 Planetary Motion Chapter 20 Bellringer A mnemonic device is a phrase, rhyme, or anything that helps you remember a fact. Create a mnemonic device that will help you differentiate between planetary rotation and revolution. Record your mnemonic device in your science journal.

47. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 Explain the difference between rotation and revolution. Describe three laws of planetary motion. Describe how distance and mass affect gravitational attraction. Objectives Section 4 Planetary Motion

48. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 Each planet spins on its axis. The spinning of a body, such a planet, on its axis is called rotation. The orbit is the path that a body follows as it travels around another body in space. A revolution is one complete trip along an orbit. A Revolution in Astronomy Section 4 Planetary Motion

49. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 Section 4 Planetary Motion Earth’s Rotation and Revolution

50. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 Johannes Kepler made careful observations of the planets that led to important discoveries about planetary motion. Kepler’s First Law of Motion Kepler discovered that the planets move around the sun in elliptical orbits. A Revolution in Astronomy, continued Section 4 Planetary Motion

51. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 Section 4 Planetary Motion Ellipse

52. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 Kepler’s Second Law of Motion Kepler noted that the planets seemed to move faster when they are close to the sun and slower when they are farther away. A Revolution in Astronomy, continued Section 4 Planetary Motion

53. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 Kepler’s Third Law of Motion Kepler observed that planets more distant from the sun, such as Saturn, take longer to orbit the sun. A Revolution in Astronomy, continued Section 4 Planetary Motion

54. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 Kepler did not understand what causes the plans farther from the sun to move slower than the closer planets. Sir Isaac Newton’s description of gravity provides an answer. Newton to the Rescue! Section 4 Planetary Motion

55. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 The Law of Universal Gravitation Newton’s law of universal gravitation states that the force of gravity depends on the product of the masses of the objects divided by the square of the distance between the objects. According to this law, if two objects are moved farther apart, there will be less gravitational attraction between them. Newton to the Rescue! continued Section 4 Planetary Motion

56. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 Orbits Falling Down and Around Inertia is an object’s resistance to change in speed or direction until an outside force acts on the object. Gravitational attraction keeps the planets in their orbits. Inertia keeps the planets moving along their orbits. Newton to the Rescue! continued Section 4 Planetary Motion

57. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 Section 4 Planetary Motion Gravity and the Motion of the Moon

58. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Formation of the Solar System Concept Map Use the terms below to complete the concept map on the next slide. Chapter 20 comets planets suns solar nebulas orbit solar systems nuclear fusion planetesimals

59. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Formation of the Solar System Chapter 20

60. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Formation of the Solar System Chapter 20

61. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu End of Chapter 20 Show

62. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation Reading Read each of the passages. Then, answer the questions that follow each passage. Chapter 20

63. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation Passage 1 You know that you should not look at the sun, right? But how can we learn anything about the sun if we can’t look at it? We can use a solar telescope! About 70 km southwest of Tucson, Arizona, is Kitt Peak National Observatory, where you will find three solar telescopes. In 1958, Kitt Peak was chosen from more than 150 mountain sites to be the site for a national observatory. Continued on the next slide Chapter 20

64. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation Passage 1, continued Located in the Sonoran Desert, Kitt Peak is on land belonging to the Tohono O’odham Indian nation. On this site, the McMath-Pierce Facility houses the three largest solar telescopes in the world. Astronomers come from around the globe to use these telescopes. The largest of the three, the McMath-Pierce solar telescope, produces an image of the sun that is almost 1 m wide! Chapter 20

65. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation 1. Which of the following is the largest telescope in the world? A Kitt Peak B Tohono O’odham C McMath-Pierce D Tucson Chapter 20

66. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation 1. Which of the following is the largest telescope in the world? A Kitt Peak B Tohono O’odham C McMath-Pierce D Tucson Chapter 20

67. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation 2. According to the passage, how can you learn about the sun? F You can look at it. G You can study it by using a solar telescope. H You can go to Kitt Peak National Observatory. I You can study to be an astronomer. Chapter 20

68. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation 2. According to the passage, how can you learn about the sun? F You can look at it. G You can study it by using a solar telescope. H You can go to Kitt Peak National Observatory. I You can study to be an astronomer. Chapter 20

69. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation 3. Which of the following is a fact in the passage? A One hundred fifty mountain sites contain solar telescopes. B Kitt Peak is the location of the smallest solar telescope in the world. C In 1958, Tucson, Arizona, was chosen for a national observatory. D Kitt Peak is the location of the largest solar telescope in the world. Chapter 20

70. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation 3. Which of the following is a fact in the passage? A One hundred fifty mountain sites contain solar telescopes. B Kitt Peak is the location of the smallest solar telescope in the world. C In 1958, Tucson, Arizona, was chosen for a national observatory. D Kitt Peak is the location of the largest solar telescope in the world. Chapter 20

71. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation Passage 2 Sunlight that has been focused can produce a great amount of thermal energy—enough to start a fire. Now, imagine focusing the sun’s rays by using a magnifying glass that is 1.6 m in diameter. The resulting heat could melt metal. If a conventional telescope were pointed directly at the sun, it would melt. To avoid a meltdown, the McMath-Pierce solar telescope uses a mirror that produces a large image of the sun. Continued on the next slide Chapter 20

72. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation Passage 2, continued This mirror directs the sun’s rays down a diagonal shaft to another mirror, which is 50 m underground. This mirror is adjustable to focus the sunlight. The sunlight is then directed to a third mirror, which directs the light to an observing room and instrument shaft. Chapter 20

73. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation 1. In this passage, what does the word conventional mean? A special B solar C unusual D ordinary Chapter 20

74. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation 1. In this passage, what does the word conventional mean? A special B solar C unusual D ordinary Chapter 20

75. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation 2. What can you infer from reading the passage? F Focused sunlight can avoid a meltdown. G Unfocused sunlight produces little energy. H A magnifying glass can focus sunlight to produce a great amount of thermal energy. I Mirrors increase the intensity of sunlight. Chapter 20

76. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation 2. What can you infer from reading the passage? F Focused sunlight can avoid a meltdown. G Unfocused sunlight produces little energy. H A magnifying glass can focus sunlight to produce a great amount of thermal energy. I Mirrors increase the intensity of sunlight. Chapter 20

77. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation 3. According to the passage, which of the following statements about solar telescopes is true? A Solar telescopes make it safe for scientists to observe the sun. B Solar telescopes don’t need to use mirrors. C Solar telescopes are built 50 m underground. D Solar telescopes are 1.6 m in diameter. Chapter 20

78. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation 3. According to the passage, which of the following statements about solar telescopes is true? A Solar telescopes make it safe for scientists to observe the sun. B Solar telescopes don’t need to use mirrors. C Solar telescopes are built 50 m underground. D Solar telescopes are 1.6 m in diameter. Chapter 20

79. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation Interpreting Graphics The diagram below models the moon’s orbit around the Earth. Use the diagram below to answer the questions that follow. Chapter 20

80. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation 1. Which statement best describes the diagram? Chapter 20 A Orbits are straight lines. B The force of gravity does not affect orbits. C Orbits result from a combination of gravitational attraction and inertia. D The moon moves in three different directions depending on its speed.

81. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation 1. Which statement best describes the diagram? Chapter 20 A Orbits are straight lines. B The force of gravity does not affect orbits. C Orbits result from a combination of gravitational attraction and inertia. D The moon moves in three different directions depending on its speed.

82. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation 2. In which direction does gravity pull the moon? Chapter 20 F toward the Earth G around the Earth H away from the Earth I toward and away from the Earth

83. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation 2. In which direction does gravity pull the moon? Chapter 20 F toward the Earth G around the Earth H away from the Earth I toward and away from the Earth

84. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation 3. If the moon stopped moving, what would happen? Chapter 20 A It would fly off into space. B It would continue to orbit the Earth. C It would stay where it is in space. D It would move toward the Earth.

85. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation 3. If the moon stopped moving, what would happen? Chapter 20 A It would fly off into space. B It would continue to orbit the Earth. C It would stay where it is in space. D It would move toward the Earth.

86. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation Math Read each question, and choose the best answer. Chapter 20

87. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation 1. An astronomer found 3 planetary systems in the nebula that she was studying. One system had 6 planets, another had 2 planets, and the third had 7 planets. What is the average number of planets in all 3 systems? A 3 B 5 C 8 D 16 Chapter 20

88. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation 1. An astronomer found 3 planetary systems in the nebula that she was studying. One system had 6 planets, another had 2 planets, and the third had 7 planets. What is the average number of planets in all 3 systems? A 3 B 5 C 8 D 16 Chapter 20

89. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation 2. A newly discovered planet has a period of rotation of 270 Earth years. How many Earth days are in 270 Earth years? F 3,240 G 8,100 H 9,855 I 98,550 Chapter 20

90. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation 2. A newly discovered planet has a period of rotation of 270 Earth years. How many Earth days are in 270 Earth years? F 3,240 G 8,100 H 9,855 I 98,550 Chapter 20

91. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation 3. A planet has seven rings. The first ring is 20,000 km from the center of the planet. Each ring is 50,000 km wide and 500 km apart. What is the total radius of the ring system from the planet’s center? A 353,000 km B 373,000 km C 373,500 km D 370,000 km Chapter 20

92. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation 3. A planet has seven rings. The first ring is 20,000 km from the center of the planet. Each ring is 50,000 km wide and 500 km apart. What is the total radius of the ring system from the planet’s center? A 353,000 km B 373,000 km C 373,500 km D 370,000 km Chapter 20

93. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation 4. If you bought a telescope for $87.75 and received a $10 bill, two $1 bills, and a quarter as change, how much money did you give the clerk? F $100 G $99 H $98 I $90 Chapter 20

94. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation 4. If you bought a telescope for $87.75 and received a $10 bill, two $1 bills, and a quarter as change, how much money did you give the clerk? F $100 G $99 H $98 I $90 Chapter 20

95. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 Section 1 A Solar System Is Born

96. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 Section 1 A Solar System Is Born

97. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 Section 1 A Solar System Is Born

98. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 Section 2 The Sun: Our Very Own Star

99. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 20 Section 2 The Sun: Our Very Own Star

100. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation Chapter 20