Formation of the Solar System

1. Chapter 20 Formation of the Solar System Table of Contents 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

2. Chapter 20 Section 1 A Solar System Is Born On your desk… -Writing Utensil -Homework (The Big Bang Theory Questions) -Science Journal 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.

3. Chapter 20 Section 1 A Solar System Is Born Essential Question • How did the solar system form? • What part did gravity play in the formation of the solar system?

4. Chapter 20 Section 1 A Solar System Is Born 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.

5. Chapter 20 Section 1 A Solar System Is Born Experiment Materials: -2 pieces of identical notebook paper -Book • Procedure: • Crumple 1 piece of notebook paper into a ball. • Place the flat paper on top of the book. Place the paper ball on top of the flat paper. • Hold the book waist high, and then drop it to the floor.

6. Chapter 20 Section 1 A Solar System Is Born Experiment Results • Analysis • Which piece of paper reached the bottom first? • Did either piece of paper fall slower than the book? Explain. • 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. Chapter 20 Section 1 A Solar System Is Born Gravity • Watch this Brain Pop clip on gravity. • Take the quiz together and keep in your science folder to study.

8. Chapter 20 Section 1 A Solar System Is Born The Formation of the Solar System • 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

9. Chapter 20 Section 1 A Solar System Is Born 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.

10. Chapter 20 Section 1 A Solar System Is Born 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. • As more collisions happened, the bodies continued to grow and eventually became the planets.

11. Chapter 20 Section 1 A Solar System Is Born Outer Planets • Gas Giants The largest planets formed near the outside of the solar system, where hydrogen and helium were located. • These outer planets grew to huge sizes and became the gas giants: Jupiter, Saturn, Uranus, and Neptune.

12. Chapter 20 Section 1 A Solar System Is Born 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.

13. Chapter 20 Section 1 A Solar System Is Born 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.

14. Chapter 20 Section 1 A Solar System Is Born How Long Did it Take? • It took about 10 million years for our solar system to form.

15. Chapter 20 Section 1 A Solar System Is Born 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.

16. Chapter 20 Section 2 The Sun:Our Very Own Star On your desk… -Writing Utensil -Science Journal -Homework (Picture/Story about formation of the solar system) 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.

17. Chapter 20 Section 2 The Sun: Our Very Own Star Story or picture of the formation of the solar system • 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. • When you are done • Turn in your work • Return to your seat quietly

18. Chapter 20 Section 2 The Sun: Our Very Own Star Essential Questions • Why is the sun important to life on Earth? • How far away is the sun from Earth?

19. Chapter 20 Section 2 The Sun: Our Very Own Star 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.

20. Chapter 20 Section 2 The Sun: Our Very Own Star The Sun Click below to watch the Brain Pop Video on the Sun. Brain Pop

21. Chapter 20 Section 2 The Sun: Our Very Own Star How far is the Sun from the Earth? 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. Chapter 20 Section 3 The Earth Takes Shape 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 journaldescribing what Earth might have been like during the first billion years of its existence.

23. Chapter 20 Section 3 The Earth Takes Shape Objectives • Describethe 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.

24. Chapter 20 Section 3 The Earth Takes Shape Formation of the Solid Earth • 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.

25. Chapter 20 Section 3 The Earth Takes Shape Formation of the Solid Earth, continued • 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.

26. Chapter 20 Section 3 The Earth Takes Shape Formation of the Solid Earth, continued • 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.

27. Chapter 20 Section 3 The Earth Takes Shape Formation of the Solid Earth, continued • 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.

28. Chapter 20 Section 3 The Earth Takes Shape Formation of the Solid Earth, continued • 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.

29. Chapter 20 Section 3 The Earth Takes Shape How the Earth’s Layers Formed • 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.

30. Chapter 20 Section 3 The Earth Takes Shape

31. Chapter 20 Section 3 The Earth Takes Shape How the Earth’s Layers Formed, continued • 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.

32. Chapter 20 Section 3 The Earth Takes Shape How the Earth’s Layers Formed, continued • 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.

33. Chapter 20 Section 3 The Earth Takes Shape How the Earth’s Layers Formed, continued • 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.

34. Chapter 20 Section 3 The Earth Takes Shape Formation of the Earth’s Atmosphere • 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.

35. Chapter 20 Section 3 The Earth Takes Shape Formation of Earth’s Atmosphere, continued • 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.

36. Chapter 20 Section 3 The Earth Takes Shape Formation of Earth’s Atmosphere, continued • 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.

37. Chapter 20 Section 3 The Earth Takes Shape The Role of Life • 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.

38. Chapter 20 Section 3 The Earth Takes Shape The Role of Life, continued • 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.

39. Chapter 20 Section 3 The Earth Takes Shape The Role of Life, continued • 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.

40. Chapter 20 Section 3 The Earth Takes Shape The Role of Life, continued • 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.

41. Chapter 20 Section 3 The Earth Takes Shape The Role of Life, continued • 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.

42. Chapter 20 Section 3 The Earth Takes Shape Formation of Oceans and Continents • 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.

43. Chapter 20 Section 3 The Earth Takes Shape Ocean Formation Click below to watch the Visual Concept. You may stop the video at any time by pressing the Esc key. Visual Concept

44. Chapter 20 Section 3 The Earth Takes Shape Oceans and Continents, continued • 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.

45. Chapter 20 Section 3 The Earth Takes Shape Oceans and Continents, continued • 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.

46. Chapter 20 Section 4 Planetary Motion 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. Chapter 20 Section 4 Planetary Motion Objectives • Explainthe difference between rotation and revolution. • Describe three laws of planetary motion. • Describehow distance and mass affect gravitational attraction.

48. Chapter 20 Section 4 Planetary Motion A Revolution in Astronomy • 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.

49. Chapter 20 Section 4 Planetary Motion Earth’s Rotation and Revolution

50. Chapter 20 Section 4 Planetary Motion A Revolution in Astronomy, continued • Johannes Kepler made careful observations of the planets that led to important discoveries about planetary motion. • Kepler’s First Law of MotionKepler discovered that the planets move around the sun in elliptical orbits.