Solar System Standard Four PDF

FOR ONLINE USE ONLY DO NOT DUPLICATE Chapter Eight Solar system Introduction In Standard Three, you learnt about components of the Solar sys...

FOR ONLINE USE ONLY DO NOT DUPLICATE Chapter Eight Solar system Introduction In Standard Three, you learnt about components of the Solar system. In this chapter you will learn about the Solar system, LY and acquire knowledge on identifying natural light in our environment. Finally, in this chapter, you will learn about the N differences between light from the Sun and that of the moon. O The concept of Solar system The Solar system is the arrangement of planets and other SE heavenly bodies in relation to their position from the Sun. The Solar system is made up of the sun, planets, asteroids, U meteoroids, comets and the moons. The sun is the biggest body of the Solar system. It is the only body in the Solar system which generates its own light and heat. The Sun is at the centre E of the Solar system surrounded by eight planets. The planets N are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus LI and Neptune. Mercury is the closest planet to the sun while Neptune is the farthest planet from the Sun. Each planet N revolves around the Sun following its path which is called an O orbit. Every planet has its own orbit. R FO 102 Social Studies.indd 102 30/07/2021 13:52  FOR ONLINE USE ONLY DO NOT DUPLICATE Figure 1 below shows the arrangement of the planets in the Solar system. LY N O SE Figure 1: The Solar system U The following poem will help you to understand the arrangement of planets in the Solar system. E Eight planets around the Sun N Listen as I describe each one. LI Mercury? Here! number one, Closest planet to the Sun. N Venus? Here number two, O Shinning bright just like new. Earth? Here! number three, R Earth is the home to you and I. FO Mars? Here number four, Red and ready to explore. 103 Social Studies.indd 103 30/07/2021 13:52  FOR ONLINE USE ONLY DO NOT DUPLICATE Jupiter? Here number five, Leading planet that is massive. Saturn? Here number six, With rings of dust and ice that mix. Uranus? Here number seven, A planet rolled high in heaven. Neptune? Here number eight, LY With one dark spot whose size is big. Exercise 1 N Answer the following questions: O 1. List the planets in the solar system. 2. Which planet is farthest from the sun? SE 3. Which planet is the largest in the solar system? 4. Which planet is the closest to the sun? U 5. What is the position of the Earth in the solar system? Activity 1 E Prepare a solar system model, the sun should be at the centre. N Use pieces of paper to make different shapes of planets. You can place an orbit using a thread. Remember the Sun should LI be large and with yellow and red colours. You can then present your work in class. N O Objects found on Earth The planet Earth consists of different things on it such as rocks, R rivers, mountains animals and plants. All together they form the FO environment. You should note that the environment consists of both living and non-living things. 104 Social Studies.indd 104 30/07/2021 13:52  FOR ONLINE USE ONLY DO NOT DUPLICATE Study the following picture then answer the questions that follow. LY N O SE Figure 2: Some of the things found on the Earth Questions U 1. Name five things found on the Earth as seen in Figure 2. 2. What other things are found on the Earth? 3. Name other five things found in the area you live. E N The Earth is the only planet in the Solar system that is currently LI known to support living organisms. It has an atmosphere filled with different gases that enable living organisms to survive. N The atmosphere consists of different gases such as hydrogen, O oxygen, carbon dioxide and nitrogen. More than one third of the Earth is covered with water. Water is an important component of the earth that supports all forms of life. R In the past, it was believed that the Earth was flat. However, FO scientific findings have proved that the shape of the Earth is spherical. 105 Social Studies.indd 105 30/07/2021 13:52  FOR ONLINE USE ONLY DO NOT DUPLICATE Two main movements of the Earth The Earth has two movements: rotation and revolution. (a) Rotation is the movement of the Earth on its own axis. It takes 24 hours or one day to make a complete rotation. (b) Revolution is the movement of the Earth around the sun along its orbit. It takes about 365 days or a year for the earth to revolve around the sun. LY The Earth consists of both living and non-living things. Examples of non-living things include oceans, buildings, rocks, mountains N and plains. Other non-living things found on earth are rivers, O the atmosphere, lakes, soil and air. Examples of living things include animals, plants, insects, birds, fish and human beings. Exercise 2 SE U Answer the following questions: 1. Why is the Earth the only planet containing living things? 2. What is the shape of the Earth? E 3. Mention the movements of the Earth. N 4. What is the importance of water to living organisms? LI Sources of natural light in the environment N Moon Sun Meteor O R FO Figure 3: Sources of natural light in our environment 106 Social Studies.indd 106 30/07/2021 13:52  FOR ONLINE USE ONLY DO NOT DUPLICATE Read the following conversation between the Sun, Moon and Meteor then answer the questions that follow. MOON: I am the moon, a natural satellite, I am proud of my size, there is no one like me. SUN: Look at you! You are not even as large as the Earth! Don’t be so proud of yourself! Now, look at me; you and your friends surround me. I am the biggest. LY MOON: Look here! your size does not matter! You can be big but lazy! You see! You just shine during the day and sleep during the night. While you are asleep, I N give the Earth natural light and the Earth loves me O for that. Now, do not envy me because I give the Earth my natural light which is not harmful. SUN : SE Ha ha ha haa! You make me laugh! Let me ask you, where do you get the light that you give to the Earth? For your information, I am the source U of that light to you and the Earth as well. I know your secrets! You reflect the light I generate to the E Earth during the night. N METEOR: Okaay! I have heard you guys! You have your merits but no one is better than me. I am the meteor LI and you cannot play around with me. None of you N has been to the Earth. You and the Sun are very far away from human beings. Whenever I go to the O Earth, human beings make me a tourist attraction. Just ask people from Mbozi in Songwe; they will R tell you about me. FO SUN: Ha ha haa!! oh, you do not know me! I am the Sun, the closest star to the Earth! I am your father and your mother. I don’t have to go anywhere. I can 107 Social Studies.indd 107 30/07/2021 13:52  FOR ONLINE USE ONLY DO NOT DUPLICATE make my own light energy and heat. You do not have that ability. That is why you go around me singing and praising me. MOON: No way! I revolve around the Earth from West to East. Through this revolution, human beings can count the days within a month. METEOR: Oooh! Who doesn’t know me? Sometimes I pass LY through the atmosphere at a very high speed and produce an amazing light! Human beings enjoy watching me. N SUN: It is okay if you underrate me! But I help plants to O make their own food. In addition, I give vitamin D to human beings. Why don’t you agree that I am the most important? SE METEOR: Dear Moon! Let us agree that the Sun is the best star. Look! It is the only star next to us; other stars U are far away from us. MOON: Okay! Let us accept that the sun is important not E only to us but also to the Earth. However, the sun should also accept that we are important! N Therefore, all of us are important. LI SUN: Yes, I agree that all of us are important to the life of human beings. N O Questions 1. Mention the objects which give out natural light? R 2. What is the main source of light energy? FO 108 Social Studies.indd 108 30/07/2021 13:52  FOR ONLINE USE ONLY DO NOT DUPLICATE Study the following picture, and answer the questions that follow. LY N O SE Figure 4: Use of Solar energy U Questions 1. What do you see in the picture? E 2. Mention the use of solar energy in your daily life. N 3. At what time of the day can people perform their activities LI and why? 4. Why is moonlight not as bright as sunlight? N 5. Why is moonlight not as hot as sunlight? O Read the following passage and answer the questions that follow. R The difference between sun-light and moon-light FO The Sun and the Moon provide light to the Earth. During the day, sun-light is very bright and this prevents the Moon from being seen. Sunlight is used for different activities. Moonlight 109 Social Studies.indd 109 30/07/2021 13:52  FOR ONLINE USE ONLY DO NOT DUPLICATE is not as bright as sunlight and it shines during the night. The Moon reflects the light from the Sun to the Earth. The Sun has stronger light energy than the Moon. Heat energy from the Sun helps in the formation of rain, but the moonlight does not. Moreover, Solar energy is used by plants to make their own food. Indeed, the Sun is very important to all living things on Earth. LY Questions 1. Which objects reflect light to the Earth during the night? N 2. Mention any three differences between the Sun and the Moon. O 3. Why doesn’t moonlight generate heat energy? 4. Mention the objects that produce natural light. SE 5. What is the main source of natural light? 6. Mention five uses of sun-light. U Activity 2 In a group of four, discuss what would happen in the absence E of the Sun. Write the answer in your exercise book. N Exercise 3 LI Answer the following questions: N 1. Draw the solar system and write down the names of its O planets. 2. Mention the benefits of the sun, moon and the meteor to R human beings. FO 3. Mention something new you have learned after studying the solar system. 110 Social Studies.indd 110 30/07/2021 13:52  FOR ONLINE USE ONLY DO NOT DUPLICATE Match the items in LIST A with the correct items in LIST B LIST A LIST B 4. Sun (a) largest planet (b) the farthest planet to 5. Earth the Sun (c) source of light 6. Jupiter LY (d) a living planet 7. Neptune (e) components of the solar system N 8. Mercury (f) the fourth planet from the Sun O 9. Orbit (g) the Earth’s path around the Sun 10.Mars SE (h) the closest planet to the Sun 11.Asteroid,Comet and Meteor (i) total number of U 12.Saturn planets (j) dwarf planet E (k) a planet with a ring N Write TRUE for the correct statement and FALSE for the incorrect statement LI 13. Meteor is the source of light on Earth. ____________ N 14. The Solar system has ten planets. ______________ O 15. The path of the planets around the Sun is called an orbit._____________ R 16. The planet with a ring is known as Mars. ______________ FO 17. The Sun revolves around the Earth during the night.__________________ 111 Social Studies.indd 111 30/07/2021 13:52  FOR ONLINE USE ONLY DO NOT DUPLICATE Vocabulary Axis an imaginary line along which a body moves Revolution movement of an object in a circular way around another Revolve move in a circle on a vertical axis Rotation an act of turning at the centre of something LY N O SE U E N LI N O R FO 112 Social Studies.indd 112 30/07/2021 13:52