Contents Ohio Revised Science Standards and Model Curriculum Correlation Chart................................................ 6 Chapter 1 Earth and Space Science............................. 13 Lesson 1 The Solar System...................................... 14 Lesson 2 More Objects in the Solar System......................... 19 Lesson 3 The Sun and Other Stars................................ 23 Lesson 4 Earth s Motions and Patterns........................... 26 Lesson 5 Seasons............................................. 31 Lesson 6 Exploring the Solar System and Beyond.................... 35 Chapter 1 Review................................................ 40 Chapter 2 Life Science......................................... 47 Lesson 7 Organisms and Their Ecosystems......................... 48 Lesson 8 Producers, Consumers, and Decomposers................. 53 Lesson 9 The Flow of Energy in Ecosystems........................ 57 Lesson 10 Partnerships in Nature.................................. 63 Lesson 11 When Ecosystems Change.............................. 67 Chapter 2 Review................................................ 73 4
Chapter 3 Physical Science..................................... 81 Lesson 12 Forces and Motion..................................... 82 Lesson 13 Measuring Forces and Motion............................ 86 Lesson 14 Light Energy.......................................... 90 Lesson 15 Sound Energy........................................ 96 Chapter 3 Review............................................... 101 Investigations.................................................. 109 Investigation 1 Exploring Reflection and Absorption................... 109 Investigation 2 Modeling the Sun and Earth......................... 119 Glossary...................................................... 131 Comprehensive Review....................................... 135 5
Chapter 1 Lesson 1 The Solar System Key Words system solar system star planet orbit revolve moon gravity model Getting the Idea Many celestial bodies, or space objects, move around the sun. Each of these bodies has its own characteristics. Earth is one of the bodies that move around the sun. Together with the sun, all of these celestial bodies make up a system. The Solar System and Planets A system is a group of parts that work together. Our solar system is made up of the sun and all the objects that move around it. The sun is the center of our solar system. The sun is also the largest object in our solar system. Our sun is a star. A star is a huge ball of hot gases that gives off its own light. The sun is only one of many stars that we can see. Eight of the objects that move around the sun, including Earth, are planets. A planet is a large, round body in space that moves around a star, such as our sun. The curved path along which a planet or other space body moves is called its orbit. The diagram below shows a planet s orbit around the sun. Direction of orbit Sun Planet NOTE: Not to scale 14
Earth and the other planets revolve around the sun. To revolve means to move in a path around another object. Planets revolve around the sun in slightly elliptical, or oval, orbits. These orbits are shaped almost like circles. Each planet has its own orbit. Planets do not give off their own light. We can see them because they reflect light from the sun. When an object reflects light, light bounces off the object s surface. Sunlight bounces off the surface of the planets. Some planets are closer to the sun than Earth is. Others are farther away. Earth is the third planet from the sun. From closest to farthest from the sun, the planets are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. The planets and their order from the sun are shown in the diagram below. Sun Mercury Venus Earth Jupiter Saturn Uranus Neptune Mars The distances between each planet and the sun are shown approximately to scale. The planet sizes are not to scale. The eight planets in our solar system are very different from one another. Each planet has its own characteristics. For example, Mars has a reddish color that comes from rustlike substances on its surface. Earth is the only planet we know of that has large amounts of liquid water on its surface. It is also the only planet known to have living things. Saturn has many rings made up of tiny bits of ice and rock. Uranus looks greenish because of gas in its atmosphere. It also has rings, but far fewer than Saturn does. Mercury, Venus, Mars, Jupiter, and Saturn can all be seen with the eyes alone. Venus is easy to see low in the sky in the early morning or evening. It looks like a very bright star. 15
Mercury, Venus, Earth, and Mars are known as the inner planets. They are small and rocky. Earth and Venus are very close in size, but Earth is larger. It is the largest of the inner planets. The inner planets revolve around the sun in shorter periods of time than the outer planets do. The outer planets are Jupiter, Saturn, Uranus, and Neptune. The outer planets are large and made up mostly of gas. They do not have solid surfaces. The outer planets are also called gas giants. The diagram below shows how large the planets are compared with each other. The order from smallest to largest is Mercury, Mars, Venus, Earth, Neptune, Uranus, Saturn, and Jupiter. The diagram cannot show the size of the sun compared with the sizes of the planets. To show that, the page would have to be hundreds of times bigger than it is. Mercury Earth Jupiter Saturn Uranus Sun Venus Mars Neptune The sizes of the planets are shown approximately to scale. The distances are not to scale. Many of the planets have moons. A moon is a natural object that moves in an orbit around a planet. The outer planets have more moons than the inner planets do. Mercury and Venus have no moons, and Earth has one small, rocky moon. Scientists are still discovering more moons orbiting the outer planets. Gravity is a force that pulls all objects toward each other. Gravity acts in the solar system. It keeps the planets in their orbits around the sun. It also keeps the moons in their orbits around the planets. You will learn about other objects in the solar system in the next lesson. 16 Chapter 1: Earth and Space Science
Lesson 1: The Solar System Focus on Inquiry A model is something that stands for a real object or system. Models help people learn about things that are hard to study. These things may be very small, such as living things you cannot see with your eyes alone. Or they may be too large or too far away, such as objects in space. A model may look very different from the real thing it stands for. But the model should show how the parts of the real thing are related to each other. For example, you can model Earth and the moon by using a basketball and a tennis ball. You model the orbit of the moon around Earth when you move the tennis ball in a circle around the basketball. Think about how you could use common objects to make a three-dimensional model of the solar system. Your model should be made with objects or materials you can find at home or in your classroom. The model should show how the sun and planets are arranged and how the planets move. Your model should also give some idea of the sizes of the planets compared with each other. Describe your model below. Tell what objects you would use for the sun and for each planet. Explain how you would show the planets motion. Then draw a diagram of your model on a separate piece of paper. Have your teacher approve your design first. Then make your model. 17
Lesson Review 1. What do Earth and Saturn have in common? A. They are the same size. B. They both give off their own light. C. They both move around the sun. D. They are both made up mostly of gas. 2. What is gravity? A. a force that pulls all objects toward each other B. a force that pushes objects away from each other C. a measure of how big an object is D. a measure of how rocky an object is 3. Something that stands for a real object or system is called A. a star. C. an orbit. B. a solar system. D. a model. 4. Which planet is farthest from the sun? A. Uranus C. Mars B. Neptune D. Jupiter 5. Which of these is the largest object in the solar system? A. the sun C. Jupiter B. Earth D. Saturn 18 Chapter 1: Earth and Space Science