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Solutions for all Natural Sciences & Technology Grade 4 Learner’s Book W Bezuidenhout J Marchant D Bosch A Scott R Engelbrecht A Volker Solutions for all Natural Sciences and Technology Grade 4 Learner’s Book © W Bezuidenhout, D Bosch, R Engelbrecht, J Marchant, A Scott, A Volker, 2013 © Illustrations and design Macmillan South Africa (Pty) Ltd, 2013 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, photocopying, recording, or otherwise, without the prior written permission of the copyright holder or in accordance with the provisions of the Copyright Act, 1978 (as amended). Any person who commits any unauthorised act in relation to this publication may be liable for criminal prosecution and civil claims for damages. First published 2013 11 13 15 17 16 14 12 0 2 4 6 8 10 9 7 5 3 1 Published by Macmillan South Africa (Pty) Ltd Private Bag X19 Northlands 2116 Gauteng South Africa Typeset by: The Design Drawer Cover image from VMS Images Cover design by Deevine Design Illustrations by: Alan Kennedy, Carla Maritz, Deevine Design Photographs by: AAI Fotostock: pp. 2, 3, 4 (fig. 1.3c, fig. 1.4), 6, 11 (fig. 1.9), 16, 21, 51, 75 (fig. 6.3 left, middle), 80, 90, 93 (fig. 7.3), 96, 105, 114 (fig. 9.1a), 117, 140, 142 (fig. 11.2 bottom right, middle left, middle), 143, 186, 195, 202 (fig. 14.13), 206, 208 (fig. 15.1 left, right), 210, 213, 220, 235, 238 (fig. 18.4); AfriPics: pp. 4 (fig. 1.3d), 7, 22 (fig. 2.10), 24, 41, 44, 46, 52, 54, 107, 114 (fig. 9.1b), 118, 119, 120, 147 (fig. 11.7c), 193, 194, 208 (fig. 15.1 middle), 214, 222, 228 (fig. 17.7), 234; Gallo Images: pp. 22 (fig. 2.8, fig. 2.9), 132, 142 (fig. 11.2 top left), 174, 192, 203; Greatstock: pp. 32, 45, 50, 72, 116 (right), 142 (fig. 11.2 top right, bottom left), 147 (left), 148, 149, 153, 205, 228 (fig. 17.8), 238 (fig. 18.5), 239 (fig. 18.6); INPRA: pp. 1, 47, 93 (fig. 7.4), 94, 224 (fig. 17.2), 238 (fig. 18.3); Jeanette Verster: p. 112; Science Photo Library: p. 70; The Bigger Picture: p. 75 (fig. 6.3 right); VMS Images: pp. 11 (fig. 1.10), 224 (fig. 17.1) e-ISBN: 978-1-4310-2589-3 ISBN: 978-1-4310-1028-8 WIP: 4125M001 It is illegal to photocopy any page of this book without written permission from the publishers. The publishers have made every effort to trace the copyright holders. If they have inadvertently overlooked any, they will be pleased to make the necessary arrangements at the first opportunity. The publishers would also like to thank those organisations and individuals we have already approached and from whom we are anticipating permission. Contents CONTENTS How to use this Learner’s Book...............................................................................vii Completing a Technology Assessment Task.......................................................... ix LIFE AND LIVING Topic 1 Living and non-living things.......................................................... 1 Living and non-living things................................................................2 Unit 1 Topic 2 Structure of plants and animals................................................. 16 Unit 1 The structure of plants..................................................................... 17 Unit 2 The structure of animals................................................................... 23 Topic 3 What plants need to grow........................................................... 32 Conditions for growth.......................................................................33 Unit 1 Topic 4 Habitats of animals...................................................................... 41 Animals need habitats..................................................................... 42 Unit 1 STRUCTURES Topic 5 Structures for animal shelters.................................................... 54 Unit 1 Animal shelters................................................................................. 55 Unit 2Technology project: Design, draw and evaluate an animal shelter................................................................................... 62 MATTER AND MATERIALS Topic 6 Materials around us....................................................................... 72 Unit 1 States of materials: Solids, liquids and gases................................. 73 Unit 2 The water cycle................................................................................84 Topic 7 Solid materials................................................................................90 Raw and manufactured materials................................................... 91 Unit 1 STRUCTURES Topic 8 Strengthening materials............................................................ 105 Ways to strengthen materials........................................................ 106 Unit 1 Topic 9 Strong frame structures.............................................................112 Unit 1 Struts and frame structures............................................................113 Unit 2Technology project: Design, make and evaluate a tower structure............................................................................... 121 ENERGY AND CHANGE Topic 10 Energy and energy transfer...................................................... 132 Energy for life.................................................................................. 133 Unit 1 Topic 11 Energy around us....................................................................... 140 Unit 1 Energy transfer................................................................................141 Unit 2 Input and output energy................................................................ 146 SYSTEMS AND CONTROL Topic 12 Movement and energy in a system.......................................... 153 Unit 1 Movement and musical instruments.............................................. 154 Unit 2Technology project: Investigate, design, make and evaluate a musical instrument...................................................................... 163 Contents ENERGY AND CHANGE Topic 13 Energy and sound...................................................................... 174 Unit 1 Vibrations and sound..................................................................... 175 Unit 2 Making sounds............................................................................... 181 PLANET EARTH AND BEYOND Topic 14 Planet Earth................................................................................ 192 Unit 1 Planet Earth.................................................................................... 193 Unit 2 Earth and space............................................................................. 200 Topic 15 The Sun........................................................................................ 206 The Sun, our closest star............................................................... 207 Unit 1 Topic 16 The Earth and the Sun............................................................... 214 The Sun is the centre of the Solar System.................................... 215 Unit 1 Topic 17 The Moon..................................................................................... 222 The Moon........................................................................................ 223 Unit 1 SYSTEMS AND CONTROL Topic 18 Rocket systems.......................................................................... 235 Unit 1 Rockets for space travel................................................................ 236 Unit 2Technology project: Design, make and evaluate a rocket model using a balloon......................................................... 244 GLOSSARY ...................................................................................................... 252 How to use this Learner’s Book Welcome to the Science and Technology Grade 4 Learner’s Book. The content in the Science and Technology Grade 4 Learner’s Book is organised according to topics and each topic is structured in the same way: Topic opener page: The topic starts with a full-colour photograph of something that is related to the content of the topic. The ‘What you will learn about’ box lists the content to be covered in the topic. There is also a section called ‘Let’s talk about ...’, which gives you an opportunity to start thinking about new things you will learn about in the topic. Units and lessons: Each topic is divided into units, which are divided into lessons. A lesson consists of content followed by a Classroom activity. Some lessons also include Practical tasks. Some of the Classroom activities might be started in class but completed at home. The lessons break up the work into small chunks of information. This helps you to make sure you know and understand a certain section of the work before moving on to the next new section of work. One Practical task per term is suggested as a Formal Assessment Task. You could be assessed on these tasks, so watch out for them. Check what you learnt: These are assessment activities. The questions are aimed to check your knowledge and test if you can do what you should be able to do at the end of the topic. Summary: Each topic ends with a summary of the work covered in the topic. You could use these summaries as study notes or to revise what you should know by the end of the topic. Extra practice: The Extra practice at the end of each topic has been included as an additional activity. You can use the questions to practise what you have learnt. vii Other features to look out for are: Word bank: These contain words that you may not understand or that you may have encountered for the first time in the text. An explanation for the word is given to enable you to understand its meaning better. Always keep a dictionary handy, because if you understand a word, learning will be a lot easier. Illustrations and photos: The illustrations and photos have been included to help you understand the written text. Use the illustrations and photos when working through the text. When you see a picture of something, you will remember it a lot better. The publisher and authors wish you all the best in your study of Science and Technology Grade 4. Good luck! viii Completing a Technology Assessment Task Solving problems to meet people’s needs is what technology is all about. The skills taught in Science and Technology will give you the skills you will need to solve various technological problems. Steps to follow when completing a Technology Assessment Task During this year you need to complete two Technology Assessment Tasks. This section explains the steps you need to follow when completing a Technology Assessment Task. It starts with a problem ... In the Technology Assessment Tasks, the problems are based on real-life examples. You design and make something to solve a given problem. Before you begin designing and making a solution to a given problem, you need to understand the problem and what is required. Understanding the given problem To understand the given problem and work out what you need to design and make, draw up: •a list of specifications •a list of constraints •a design brief. ix Specifications, constraints and design briefs Specifications are the things that must be included in your product or system. Constraints are all the limitations that have been placed on the design. To draw up your list of specifications and constraints, ask yourself these questions: • What do I need to make? • What will it be used for? • Who will use it? • How big does it need to be? • Do I need to use any specific materials? • Should I include anything specific in my design? Once you have drawn up your list of specifications and constraints, you can work out a brief statement of what you have to design and make to solve the problem. This is called a design brief. A design brief always starts with ‘Design and make a…’. The design brief, and your list of specifications and constraints, will help you to understand the problem and what you need to do to solve the given problem. Help tasks Before you can begin solving a given problem, you may need to gain some new technological skills. You then need to work through different help tasks to learn these skills. Help tasks could include learning how to cut, saw, hammer or join. You may need to work through more than one help task per problem. Solve the problem using the technological design process Once you understand the problem and you have learnt all the skills needed to solve the problem, you can begin solving it. To solve a problem you need to work through the technological design process. x The design process has five main steps. These are: • investigating • designing • making • evaluating • communicating. Usually you will work through these steps of the design process in this order, but sometimes you may find it easier to change the order, depending on the problem you want to solve. Communicating also forms part of the design process. You need to communicate the steps of the design process to others. There are a few ways of doing this. One way is to record everything in a book or portfolio. Another way is to do a presentation. In the design process one step leads on to another. There is no definite place where you have to stop working through the design process. Sometimes, after evaluating a design idea or the finished product, you may find the need to work through the design process again. There is nothing wrong in doing this. It is how technology solutions are improved. xi How then do we work through each step of the design process? Investigating When you investigate, you gather information about a specific thing. Before solving a problem you need to collect information that you could use to solve the problem. You can get information in different ways. The ways that you choose to use to collect the information depend on the problem. Sometimes you may need to find information in books or magazines, or on the internet. Sometimes you need to ask other people questions to gather information. Learning a new skill is also part of investigating. Designing After you have investigated the problem, you will have some information to help you solve the problem. You may also have a few ideas of possible solutions to the problem. You are now ready to begin designing a solution to the problem. Start the designing part of the process with several ideas. Make drawings of the different ideas. The drawings should be neat and detailed, and should always have labels. The labels explain the drawing. Choose the design idea that will best solve the problem. Write down the reasons for the choice that you have made. Make a clear final drawing of the best idea. Making After completing the design you can make the product or system that is a solution to the problem. Before you make the product or system, you need to draw up a step-by-step plan of how to make the product or system. In the step-by-step plan you need to indicate necessary safety precautions to take and the tools and materials that should be used to make the product or system. Using the step-by-step plan you then make the product or system, skilfully and safely, using the right tools and materials. xii Evaluating Once the product or system has been made, you need to test it or evaluate it. This means that you need to see if it solves the problem it is meant to solve. Suggest where and how the design could be improved or modified to make it solve the problem better. Communicating Communicating is an important part of the design process. When you communicate you are making a record of how you progressed through the design process until you found a solution to the problem. Remember that there can be many ways to solve a problem; not everyone will solve a problem in the same way. Enjoy doing technology! xiii Topic 1 Living and non-living things What you will learn about in this topic • Living things • Non-living things Let’s talk about living and non-living things In the picture you can see grass, children and gardening tools. You can also see lots of dry leaves. Which of these things are living? And which are non-living things? How do you know the difference between living and non-living things? Is there anything that once was alive but is now dead? Why do you say so? Topic 1 Living and non-living things • 1 Unit 1 Living and non-living things What you know already The things in the world around us can be living or nonliving. Plants, animals and humans belong to the group of living things on Earth. Examples of non-living things are rocks, water and human-made objects such as cars. Around us, we can also see things that once lived but are now dead, for example dry wood and fossils of dinosaurs. ck Che elf Are you living or non-living? Explain what made mys you decide this. Lesson 1 There are many different kinds of living things There are many different kinds of living things on Earth. They have different sizes and shapes. Some are brightly coloured and some look dull. Some live on land and some live in water. Some can walk, some can fly, and some can swim. Some cannot rhizoids move about but they can twist and turn. Living things are called organisms. Word bank hand lens: a kind of magnifying glass used in science class organism: a living thing spores Sometimes, when food starts to decay, you can see things growing on it, especially on bread and fruit kept in a dark cupboard. If you look closely with a hand lens, you will see something that looks like the picture in Figure 1.1. It is not a plant or an animal. This living thing is called bread mould. 2 • Topic 1 Living and non-living things sporangium sporangiophore Figure 1.1 Bread mould Life and living Word bank enlarge: make bigger germs: small living things that cannot be seen with the naked eye microscope: an instrument with lenses to enlarge something that is too small to see with the naked eye Germs are living things that are so small that they cannot be seen with your eye. You need a microscope to see them. A microscope is an apparatus that is used to enlarge things so that we can see them better. Figure 1.2 shows a microscope picture of germs that are found in our world. Some germs can make you sick. The type of germ in A can cause a sore throat. The type of germ shown in B is found inside your body and sometimes on your skin. Washing your hands with soap and water after you have been to the toilet kills these germs, so that you will not get sick. A B Figure 1.2 Germs are so small that they can only be seen through a microscope. Classroom activity 1 1. The pictures in Figure 1.3 show animals and plants. A B Figure 1.3 Examples of living animals and plants Topic 1 Living and non-living things • 3 C D Figure 1.3 Examples of living animals and plants (continued) a) Name each animal or plant in the pictures. b)Which of these living things live on land and which live in water? 2. Figure 1.4 shows pictures of animals called insects. a) Name each insect. b)Insects are much smaller than the animals shown in Figure 1.3. How big do you think are each of these insects? Show with your fingers or hands. A B Figure 1.4 Insects are very small animals. 4 • Topic 1 Living and non-living things Life and living Lesson 2 Living things carry out all life processes The seven life processes Living plants and animals carry out the seven life processes. Living things: • need food Word bank • can grow • reproduce and have offspring offspring: the young or • need air to breathe baby of a living organism • excrete waste • have senses to respond to their environment • can move by themselves. Feeding or nutrition All living things need food for energy. Animals and humans need to find food from their environment, while plants can make their own. Figure 1.5a) Living things need food. Growth All living things grow. Growth could be an increase in size or mass or a change of shape. Figure 1.5b) Living things can grow. Reproduction All living things reproduce to produce offspring. For example, humans give birth to babies, cats produce kittens and birds lay eggs from which chicks hatch. Plants also reproduce. New plants can grow from seeds or from a part of the parent plant such as a root, a stem or a leaf. Figure 1.5c) Living things reproduce. Topic 1 Living and non-living things • 5 Breathing All living things need air to stay alive. Animals and plants take in oxygen from air and release carbon dioxide. Figure 1.5d) Living things Excretion need air. All living things must get rid of waste products formed in their cells. For example, the carbon dioxide that you breathe out is a waste product. When you urinate you get rid of waste products that were formed in your body. Sensing Figure 1.5f) Living things can sense changes in their surroundings. ll living things respond to changes in A their surroundings. Animals have sense organs such as eyes, ears, noses, tongues and skin. Animals use their sense organs to stay aware of what is happening around them. When they smell or see food, they can move towards it. If an animal detects an enemy, it can react by either fleeing or attacking. Figure 1.5e) Living things excrete waste products. Plants can sense changes in light and water around them. Their stems and leaves grow towards light. The roots of plants grow towards water. Movement All living things move. Animals can move from one place to another to find food or escape from danger. Although plants are rooted in one place, they do move. Their stems and leaves move by growing or turning slowly towards light. Their roots move by growing or turning slowly towards water. 6 • Topic 1 Living and non-living things Figure 1.5g) Living things can move. Life and living Classroom activity 2 1. a)Copy the table in your exercise book and then describe how a bird carries out the life processes. ‘Sensing’ has been done for you. Life process Example in a bird Feeding Growing Reproducing Breathing Excreting Sensing Sees food with its eyes Moving b) Does a bird perform all seven life processes? c) Is a bird a living or a non-living thing? 2. We can use a list of the seven life processes as a checklist to see if something is living or non-living. Write a checklist to see if something is living. Lesson 3 Living things that appear to be non-living Figure 1.6 Plant seeds Word bank Seeds look dead, but can grow into a living plant if they are given light, warmth and water. Things that appear to be dead but are still living are dormant. Given the right conditions, seeds will germinate. A new plant, called a seedling, will grow from the seed. The seedling will develop into a full-grown plant. Both the seedling and the full-grown plant are able to perform the seven life processes. dormant: in a state of rest germinate: when a new plant grows from a seed seedling: a young plant that grows from a seed Dried beans are the seeds of a bean plant. In the following practical activity, you will investigate how a bean seedling grows. Topic 1 Living and non-living things • 7 Practical activity 1 Investigate germinating bean seeds This is a prescribed activity. You will do this activity over time while you continue with other work. Aim To investigate if a dried bean will germinate and grow given the right conditions You will need: • a few dried beans • a saucer or small container • a little water • paper towel or cotton wool Word bank Method 1. Wet the paper towel with some water. 2. Place the beans between two layers of the moist paper towel. 3. Place the paper towel containing the beans in a saucer or small container. 4. Place the saucer or container in a warm spot in the classroom. 5. Observe what happens to the beans every day for one month. Remember to keep the paper towel moist throughout the investigation. 6. You will continue with this practical activity in Topic 3 (What plants need to grow). bean seeds cotton wool saucer Figure 1.7 Germinating bean seeds 8 • Topic 1 Living and non-living things aim: what you want to do method: the steps that explain how to do something Life and living Questions 1. Why are the dried beans placed between layers of moist paper towel? 2. Why are the beans placed in a warm spot in the classroom? 3. Name two life processes that you can observe in the germinating beans. Explain your answer. 4. What is your conclusion: is a dried bean seed living or non-living? Explain your answer. ry yeast, used for baking bread, looks dead and appears not to D be living. But given the right conditions it will become active and living. When dried yeast is mixed with warm water and sugar, it becomes active and performs the seven life processes. In the next practical activity you will see how yeast can become active in the right conditions. Practical activity 2 Growing yeast This is a prescribed activity. Aim To investigate if dry yeast will grow given the right conditions. You will need: • half a teaspoon of dry yeast • a teaspoon of sugar • a small container or a cup • a stirring rod or a spoon • some warm tapwater Topic 1 Living and non-living things • 9 Method 1.Add the dry yeast and sugar to half a cup of warm but not boiling water. 2.Stir the mixture with a spoon. 3.Allow the mixture to stand for about 10 minutes in a warm spot in the classroom. 4. Observe what happens. dry yeast a) b) gas bubbles warm water yeast and Questions sugar 1. Why do we add warm water and sugar to the dry Figure 1.8a) Dry yeast granules and b) yeast mixed yeast? into warm sugar water 2. Why should you not add boiling water to the dry yeast? 3. Explain why dry yeast can be classified as living although it looks dead. Challenge Yeast is used to bake bread. Find out why. An egg appears to be non-living. If a bird sits on the egg to keep it warm, a chick could hatch from the egg. The chick will be able to perform all seven processes of life. Word bank hatch: when a chick comes out of an egg Classroom activity 3 Look at the pictures on the next page of a bird’s hatching egg: 10 • Topic 1 Living and non-living things Life and living Figure 1.9 A hatching egg 1. Look at the shell of the egg in the picture on the left. Although the egg appears to be dead, something is breaking the shell. How do you think the egg shell breaks? 2. The picture on the right is a picture of a hatched egg. a) What can you see coming out of the egg? b) What has happened inside the egg? 3. What does an egg need to hatch? 4. Is an egg living or non-living? Explain your answer. Lesson 4 Non-living things Non-living things cannot perform any of the seven life processes. A bin is a non-living thing. It is made of metal and feels hard and cold when we touch it. It is a human-made object. A bin does not change size or shape once it has been made. It cannot move, eat, drink, reproduce or breathe. Figure 1.10 A metal bin on-living things cannot do some of the things that N living things can do on their own. For example, a car is a non-living thing. It can move, but not on its own. A car needs an engine to make it move. Water, rock, wind and sand are non-living. They show no or only some characteristics of life. Topic 1 Living and non-living things • 11 Some things were once alive but are now dead, for example wood or dry leaves that fell from a tree. Objects made from once-living things are non-living. For example, a chair made from wood is a non-living thing. Classroom activity 4 Look at the pictures in Figure 1.11. Classify each object as living or non-living. 1. 3. 2. 4. 5. 6. 7. 8. 9. 11. 10. 12. Figure 1.11 Living and non-living things 12 • Topic 1 Living and non-living things Life and living a)Draw a table like the one shown here in your exercise book. b)Write the number and the name of each object in either the living or the non-living column. The first one has been done for you. c)Explain to your partner why you sorted the objects the way you did. Living things Non-living things 1. Rock Challenge Find pictures in magazines that show the seven life processes. Bring the pictures to class. Make a poster for each life process. Display the poster in your classroom. Check what you learnt 1. Classify the objects in the pictures as living or non-living. (7) Topic 1 Living and non-living things • 13 a)Draw a table in your exercise book as shown here. b)Identify the objects and then list them in the table. c)Use a tick mark to show whether the object is living or non-living. d)Discuss your reasons for saying why the object is living or non-living with a partner and write them in the table. The first one has been done for you. Object Tree Living Non-living Reason Performs all seven life processes. 2. Are all non-living things made by humans? Give examples to help explain your answer. (3) [10] Extra practice 1. Make a crazy sentence with the first letter of each life process to help you remember them. Here’s an idea: Brown rabbits move silently following green earthworms. 2. Explain the difference between non-living and dead things. 3. Make a picture poster of living things. Find pictures in a magazine or draw your own. 14 • Topic 1 Living and non-living things Life and living Summary • Non-living things can perform no or only some life processes. • In the right conditions, some things that appear to be non-living will come ‘alive’, for example dry yeast, dried beans and a bird’s egg. • Some things were once alive but are now dead, for example wood and dry leaves. Moving – when an organism changes its position or orientation Sensing – detecting changes in environment through sense organs Excreting – to get rid of waste products Feeding – using food for energy Life processes Breathing – taking in oxygen and releasing carbon dioxide Growing – increasing in size or changing in shape Reproducing – to produce offspring Topic 1 Living and non-living things • 15 Topic 2 Structure of plants and animals What you will learn about in this topic •The structure of plants • The structure of animals Let’s talk about the structure of plants and animals The picture shows a bird on a protea bush. Plants and animals are both living things, but they do not look the same. Which features can you see in the bird that you have also seen in other animals? Which features of the protea bush have you also seen in other plants? Why do you think plants and animals look different? 16 Structureof ofplants plantsand andanimals animals • Topic 2 Structure Life and living Unit 1 The structure of plants What you know already In Topic 1 (Living and non-living things) you learnt that plants are living things. They are able to perform all seven of the life processes. You also learnt that a seed will germinate and grow into a plant given the right conditions. 1. Name the different parts of a plant. ck e h C elf 2. What does ‘germinate’ mean? mys 3. Why is a plant classified as a living thing? Lesson 1 Structure of plants There are many different kinds of plants. Although plants come in different shapes and sizes, they all have the same basic structure. Figure 2.1 shows the basic structure of a plant. bud Word bank flower function: a specific task structure: the way in which different parts of something have been put together to form a whole stem fruit leaf root Figure 2.1 Basic structure of a plant All plants have roots, stems and leaves. Some plants also have flowers and fruits, and some can be grown from seeds. Each part of the plant has a specific job, called a function. Topic 2 Structure of plants and animals • 17 Roots The roots of a plant grow below the ground. Roots keep the plant firmly anchored in the ground. Roots also absorb water for the plant. Not all plants’ roots look the same. Some plants have thick, straight roots that grow deep into the ground. Other plants have fine roots that grow sideways. Stems The stem of a plant grows above the ground. The stem supports the leaves and buds, and flowers and fruit if the plant has any. The buds on the stems can grow into another stem or a flower. Stems can be hard and brown or soft and green. Leaves All leaves have the same basic structure, even if they look different. Figure 2.2 shows the basic structure of a leaf. The leaves are attached to the stem by a leaf stalk. The flat surface of a leaf is called the blade. Some plants have long, thin leaves. Other plants have wide leaves, which come in different shapes. The leaves of a plant are usually green. Green leaves contain a pigment that helps the plant to make food by using energy from the sun. Flowers Many plants have flowers. Plants that have flowers are called flowering plants. Flowers are responsible for reproduction in a plant. Flowers all have the same basic structure, even if they differ in size, shape and colour. blade vein leaf stalk stem Figure 2.2 Basic structure of a leaf petal stamen stigma Figure 2.3 shows the basic structure of a flower. A flower is made up of different parts. Each part has its own function. For example, the stamen produces pollen and the colourful petals attract pollinators like bees and butterflies. 18 • Topic 2 Structure of plants and animals Figure 2.3 Basic structure of a flower Life and living Fruit Figure 2.4 shows an apple and an orange. When you cut open these fruit you can see the seeds of the plant. A fruit forms around a seed to protect it. Many plants form fruit that can be eaten by humans and animals. Once the fruit has been eaten, only the open seeds are left. In the right conditions, new plants can grow where the seeds fall. skin or peel seed(s) flesh of the fruit Figure 2.4 Fruit cut open to show the seeds inside Word bank bud: a small part on the stem of a plant that can grow into a flower or another stem pigment: a coloured substance pollinator: an animal that carries pollen from one flower to another seed: the part of a flowering plant that grows into a new plant Seeds Inside a seed is a small developing plant. It is called the embryo. The hard covering around the outside of a seed is called the seed coat. This protects the seed from drying out. The seed leaves supply a germinating seed with food until the first leaves of the new plant have grown. The developing plant will grow a stem, leaves and roots. embryo seed leaf (food store) seed coat Figure 2.5 Internal structure of a seed Topic 2 Structure of plants and animals • 19 Classroom activity 1 1.Study Figure 2.6 and answer the questions that follow. 1 2 3 4 5 Figure 2.6 a)Give the diagram in Figure 2.6 a suitable heading. b)Label the parts numbered 1–5. Write down the number and the correct word next to it. c)Write down the name and number of the part that is found underground. d)Write down the number and name of the part that is responsible for reproduction of the plant. e)Write down the number and name of the part of the plant that contains seeds. 2.Draw a fruit cut in half to show the inside. Label each part. 20 • Topic 2 Structure of plants and animals Life and living Lesson 2 Visible differences between different plants There are many different kinds of flowering plants. The roots, stems, leaves, flowers, fruit and seeds of a bean plant look very different from those of a marula tree or a mealie plant. The mealie plant A mealie plant has many thin, white roots that grow below the ground. At first, the stem is soft and green, but it becomes lighter in colour and harder as the plant grows older. A mealie plant has long, thin leaves. The plant forms groups of many light brown or red flowers on a stalk. These will later become the mealie cobs we eat. If you grind mealies you can make maize meal for mealie pap, a traditional South African food. group of flowers stem leaf long thin roots Figure 2.7 A mealie plant The bean plant Bean plants have a main root that grows from the stem. Many thin roots grow sideways out of the main root. The stem remains soft and green throughout the plant’s life. Green, heart-shaped Topic 2 Structure of plants and animals • 21 leaves grow from the stem. The beans that we eat form from small white-yellow, pink or even red flowers. flower leaf stem side root main root Word bank Figure 2.8 A bean plant The marula tree The marula tree is indigenous to South Africa. The tree grows from a seed and can become up to 18 m tall. The tree has a very big main root, which grows deep into the ground. Light yellow side roots grow from the main root. The tree has a single big brown stem out of which branches spread wide. Large, round fruit form from the flowers. Inside the fruit is a large pip that contains the seeds. Ripe marula fruit have a light yellow skin. Animals eat the fruit and seeds. indigenous: referring to plants and animals that are found naturally in a specific region Figure 2.9 Marula tree People use marula fruit in food and drinks. The leaves and bark are sometimes used to treat stomach aches. 22 • Topic 2 Figure 2.10 Marula fruit Structure of plants and animals Life and living Classroom activity 2 1.Copy and complete the following table to describe the visible differences between a mealie plant, a bean plant and a marula tree. Some parts have already been done to help you. You can look at the pictures in the lesson and real examples of the plants if your teacher has any. Part of plant Mealie Roots Bean Marula tree Small, thin, white roots that grow from the stem Stems Soft and green Leaves Flowers Fruit Mealie cob with seeds Seeds Large, broad, white seeds Challenge Find out about other edible plants that are indigenous to South Africa. Unit 2 The structure of animals What you know already There are many different types of animals. Animals are living things and perform all seven life processes. Topic 2 Structure of plants and animals • 23 ck Che elf Look at the picture of the lion in Figure 2.11. Give seven reasons why you would classify a lion as a living thing. mys Lesson 1 Basic structure of animals The structure of an animal includes the head, tail, body, limbs (legs and wings) and sense organs. The structure of an animal is suited to the way the animal lives, for example, how it finds and eats its food and the way it reproduces. You can look at the visible features of an animal to see its structure. Word bank limbs: the parts of an animal used for movement, for example arms, legs and wings feature: a characteristic Classroom activity 3 1.Look at Figure 2.11 and draw the lion in your exercise book. 2. Label the following visible features: a)tail b)body c)legs d)head e)ears f)eyes g)nose h)mouth. 3. Give your drawing a suitable heading. Lesson 2 Visible differences between animals Although all animals have the same basic structure they do not all look the same. The differences we can see are called visible differences. Let’s look at the visible differences in the body structure of a locust, a dove and a gemsbok. 24 • Topic 2 Structure of plants and animals Figure 2.11 A lion Life and living Structure of a locust Figure 2.12 shows the structure of a locust. A locust is an insect. Figure 2.12a) A jumping locust { body { antenna compound eye simple eye mouthparts head foreleg midleg Figure 2.12b) The body structure of a locust • • Word bank insect: a small animal with six legs hindleg Head: The sense organs are found on the head of the locust. The sense organs help the locust to find food and sense danger. Two compound eyes and three simple eyes are used for vision. The two antennae are used for smell and touch. The mouthparts are used to eat leaves. Body: A locust has a long, narrow body. It does not have a tail. The back part of the body contains the male or female structures of the locust. The limbs consist of three pairs of legs and two pairs of wings. The wings are used for flying. A locust uses its forelegs and the midlegs for walking, and its large hind legs are used for jumping. A hard outer covering protects the locust’s head and body. Structure of a dove You can see the structure of a dove in Figure 2.13. Figure 2.13a) A dove in flight Topic 2 Structure of plants and animals • 25 eye nostril beak position of ear neck wing { head { body { tail leg toe with claws tail feathers Figure 2.13b) The body structure of a dove • Head: The sense organs are found on the head. A bird has two eyes. Good sight helps the bird to find food and its nest. Eyelids can close the eyes. Behind each eye is an ear opening, which is covered with feathers. This ear opening is used for hearing. A bird has a beak with a tongue for tasting, but no teeth. The bird uses its beak to eat food and protect itself. A bird has two nostrils near the beak, which are used for smell. Body: The body of a bird has a rounded shape. It is covered with feathers, to keep the bird warm and dry. A bird has wings and legs as limbs, which it uses to reach its nest, find food or a mate, and escape from dangers. The feathers that cover the wings make the wings larger and help the bird to fly. The two legs are covered with hard scales, not with feathers. The feet are used for walking and can claw around tree branches. Some birds use their claws to catch and hold on to their food. Tail: A bird’s tail is covered with feathers. The tail is used to steer the bird during flight, almost like a driver uses the steering wheel of a car. • • 26 • Topic 2 Structure of plants and animals Word bank scales: hard skin that covers the body of fish and feet of birds Life and living The structure of a gemsbok Figure 2.14 shows the structure of a gemsbok. horns ear eye { head neck mouth { body tail front legs hind leg hoofs Figure 2.14 The body structure of a gemsbok • Head: The sense organs are found on the head. A gemsbok • • has very good eyesight, hearing and smell, which help it to become aware of dangers. A gemsbok has a snout with a nose for smelling and a mouth with teeth and a tongue for tasting. The tongue helps the gemsbok to hold the grass while the teeth cut the grass. A gemsbok has long spear-like horns at the front of its head, which it can use to protect itself against dangerous animals. Body: The body of a gemsbok is covered with fur. Gemsbok live in hot desert areas and the fur protects them against the heat. The gemsbok has four legs and a thick neck. The legs do not have feet and toes but a hoof. The hoof is hard and helps the animal move over rough ground. The gemsbok can run very fast. A gemsbok uses its limbs to find food, to find a mate to have babies and flee away from its enemies. Tail: The tail is long and ends in long hair. The gemsbok uses its tail to sweep away irritating insects. Topic 2 Structure of plants and animals • 27 Classroom activity 4 1. Study Figure 2.15 to answer the following questions. 1 B { { A 7 6 2 5 3 4 Figure 2.15 a)Identify this animal. b)Provide labels for numbers 1 to 7. c)Write down the names of the body parts labelled A and B. d)On which body part do the sense organs appear? e)Which sense organs can you identify? f)Which limbs are used for movement? 2.Copy and complete the following table to describe the visible differences in the body structures of a locust, a dove and a gemsbok. You can use the Figures 2.12, 2.13 and 2.14 to help you. Feature Size Body structure Body covering Sense organs Limbs Locust Very small Head, body Hard shell Eyes, antennae Legs, wings Dove Gemsbok Challenge During the next week, collect pictures of animal body parts from magazines, posters, newspapers or adverts. Make a poster to show the different heads, tails and limbs of animals. Give your poster a big, bold heading. 28 • Topic 2 Structure of plants and animals Life and living Check what you learnt 1. Label the structure of the plant shown in Figure 2.16. a) (5) b) c) d) e) Figure 2.16 A dandelion 2.Label the body structure of the giraffe shown in Figure 2.17. a) (5) b) c) d) e) Figure 2.17 A giraffe 3.Label the body structure of the eagle shown in Figure 2.18. (5) a) b) c) d) Figure 2.18 An eagle e) 4.Write a sentence to explain one main difference between the body structure of the giraffe and the eagle. (1) [16] Topic 2 Structure of plants and animals • 29 Extra practice 1. Give the correct term for: a)the part of a plant that anchors it to the ground b)the green part of a plant that makes food c)the part of a plant that absorbs water. 2.Copy and complete the following table in your exercise book. Part of plant Function Roots Stems Leaves Flowers Seeds 3.‘Although a plant has no limbs, it can still move.’ Is this statement true? Explain your answer. 4.For each of the following plants or animals, find the feature that does not belong: a) Pine tree: roots, stems, body, leaves b) Fish eagle: head, tail, body, stem, wings c) Cape cobra: head, roots, body, tail d) Warthog: fruit, head, tail, body, limbs e) Protea: stem, leaves, limbs, flower, roots 30 • Topic 2 Structure of plants and animals Life and living Summary • The basic structure of plants includes roots, stems, leaves, flowers, fruits and seeds • There are visible differences between plants • Plants vary in size, shape and colour of the roots, stems, leaves, fruits and seeds • The basic structure of animals includes the head, tail, body, limbs and sense organs • There are visible differences between animals • Animals vary in size, shape, body covering and sense organs. Topic 2 Structure of plants and animals • 31 Topic 3 What plants need to grow What you will learn about in this topic • Conditions for growth Let’s talk about what plants need to grow The picture shows a young plant being planted. What does this young plant need to grow? Can you see some of the things that a plant needs to grow in the picture? Name them. This young plant was grown from a seed. What part of a plant can you use to grow a new plant if you do not have seeds? 32 Whatplants plantsneed needto togrow grow • Topic 3 What Life and living Unit 1 Conditions for growth What you know already In Topic 1 (Living and non-living things) you learnt about living and non-living things. You learnt about the life processes. Growing is one of the life processes. In the right conditions a dormant bean seed can develop into a new plant. 1.Are plants living or non-living things? Give reasons ck for your answer. Che elf s my 2.What term is used to describe the process when a seed starts to grow? 3.What does a bean seed need to grow into a new plant? Word bank absorb: to take up habitat: the natural home of a plant or animal where it gets everything it needs to survive Lesson 1 Plants need light, water and air to grow Plants are living things. They can grow. Plants need light, water, soil and air to grow. Plants also need to absorb nutrients from the soil to grow. If one of these things is missing a plant cannot grow. Figure 3.1 shows healthy, growing pot plants in a classroom. Plants need a place to grow. The place or area where a plant lives is called a habitat. The habitat of a plant provides the plant with all the things it needs to grow, namely light, water, air and soil. You will learn more about different habitats in Topic 4 (Habitats of animals). Figure 3.1 Plants need light, water, air and soil to grow. Topic 3 What plants need to grow • 33 Plants need light to grow Plants need light to grow. Plants get light from the sun to make food. The plant uses the food to grow. The leaves of a plant always turn towards the sun to catch as much light as they can. Plants need water to grow Plants need water to grow. Plants use water to make food. Plants get water from the soil. The roots of a plant absorb the water from the soil. The water from the soil contains nutrients that the plant uses to grow. The roots of a plant always grow towards water. Word bank nutrients: minerals that help an organism to grow well Plants need air to grow Plants need air to grow. Air contains two gases, namely oxygen and carbon dioxide. Plants use carbon dioxide to make food and in the process give off oxygen. All living things need oxygen for breathing. Practical activity Investigate where plants grow This is an optional activity. Aim To find out where plants grow You will need: • a notebook or piece of paper • a pencil Method 1. Walk around the school grounds. 2. Make a list of dry and shady areas. 3. List the areas where the plants grow. 4. List the areas where the plants do not grow. 34 • Topic 3 What plants need to grow Life and living Questions 1. In which area do the plants grow the best? Say why. 2.In which area do the plants not grow that well? Say why. Classroom activity 1 1.Draw a mind map to show what a plant needs to grow. 2.In each case, write one sentence for your answer. What do you think will happen to a healthy pot plant if: a) the plant is placed in a dark cupboard? b) the plant is not watered? c) the plant is placed in an airtight plastic bag? d) the soil is removed from the pot? 3.Plants might not grow easily in all the areas around your school. In some areas the buildings block the sunlight. Bricks and concrete do not allow rainwater to soak into the ground, and the soil might be dry. When people walk across the grounds they could trample plants that are trying to grow. a)Make a list of some dry and some shady areas around your school. b)Do any plants grow in these places? Write a sentence to explain your findings. Lesson 2 New plants can grow from seeds Plants can grow from seeds. In Topic 1 (Living and non-living things), you learnt that seeds are dormant until the conditions are right for growth. Given the right conditions seeds germinate. Seeds need water and warmth to germinate and grow into a new plant. Figure 3.2 shows how a seed germinates and grows into a new plant. Topic 3 What plants need to grow • 35 seed leaves (cotyledon) first leaves (plumule) young stem young root (radicle) seed coat 1 2 3 4 5 Figure 3.2 A germinating seed 1.The seed is planted in the soil. The seed gets warmth and water in the soil. 2.The seed absorbs water and starts to swell. The seed coat wrinkles and then splits open. The first thing to appear is the young root. The young root is called the radicle. 3.The stem straightens, carrying the seed leaves along. The seed leaves are called the cotyledons. The seed leaves appear above the soil. The seed leaves supply the seedling with food until it has grown new green leaves. 3.The radicle grows bigger. The first leaves of the seedling appear. The first leaves are called the plumule. The seedling can make its own food as the first leaves grow bigger. For the young plant to continue growing, there needs to be enough light, water, air and soil. Practical activity Project(20) Investigate how seedlings grow You started this practical activity in Topic 1 (Living and non-living things) when you investigated how bean 36 • Topic 3 What plants need to grow Word bank cotyledon: seed leaf plumule: the first leaves of a seedling radicle: young root Life and living seeds germinate. You are now going to continue with the investigation and observe how the bean seedlings grow. Aim To investigate how seedlings grow You will need: • an empty 2ℓ ice cream container • soil • a small spade • seedlings (from Topic 1) • water • a ruler or measuring tape Safety warning Always wash your hands with soap and water after you have worked with soil. Method 1. Fill the ice cream container halfway with the soil. 2.Plant the seedlings in the soil. Remember to leave some space between the seedlings. 3. Water lightly. 4. Place the container in a sunny spot. 5. Water lightly each day. 6.Write down your observations every day. Use a table such as the one shown here. Results Day Observations 1 Seedlings planted Length of root Length of stem Topic 3 What plants need to grow • 37 Classroom activity 2 1. a)Draw four steps to show how a seed germinates and grows into a new plant. b)Label the drawing and give the drawing a heading. Lesson 3 New plants can grow from cuttings Word bank In the previous lesson you learnt that new plants can grow from seeds. New plants can also grow from cuttings. A cutting is a piece of a plant, for example a stem or a leaf, cut from another plant and used to grow a new plant. The plant from which the cutting is taken is called the parent plant. If the cutting is given light, water, air and soil, it will live and grow into a new plant. cutting: a piece cut from a parent plant to grow into a new plant parent plant: the plant that a cutting is taken from Practical activity Project(20) Investigate if a new plant will grow from a cutting Aim To find out if a new plant will grow from a cutting You will need: • a knife or scissors • a cutting from a parent plant, for example, a geranium plant • a glass jar or bottle with water • a pot with soil Safety warning Be careful not to cut yourself when using the knife or scissors. 38 • Topic 3 What plants need to grow Life and living Method 1.Use a knife or scissors to cut off a shoot from the parent plant. 2.Cut off the leaves at the bottom of the shoot. 3. P lace the cutting in a jar with water. Place the jar in a light, airy spot in the classroom. Keep the cutting in the water for several weeks. Keep adding fresh water. 4.Tiny, white growths will appear on the parts of the cutting that are in the water. Plant the cutting into a pot of soil. 5.Water the new plant well and regularly. Questions 1.Why do you need to keep adding fresh water to the jar with the Figure 3.3 Growing cutting? a new plant from a 2. Why do you need to place the jar cutting with the cutting in a light, airy spot in the classroom? 3.What are the tiny white growths that appear on the cutting? Topic 3 What plants need to grow • 39 4. a) Draw the cutting in the jar. b)Label the drawing. c)Give your drawing a heading. 5. Why do you need to plant the cutting in soil? 6.What is your conclusion: can a new plant be grown from a cutting if given the right conditions? Classroom activity 3 1. What is a cutting? 2. What parts of a plant can be used as a cutting? 3. What is the plant called that a cutting is taken from? 4.What conditions does a cutting need to grow into a new plant? Extra practice 1. List three things that plants need to live and grow. 2. Which two things does a seed need to germinate? 3.Describe the first two changes you would observe in a germinating seed. Summary Plants can be grown from cuttings or seeds Seeds need water and warmth to germinate. What plants need to grow Plants need light, air, water and soil to grow. 40 • Topic 3 What plants need to grow Topic 4 Habitats of animals What you will learn about in this topic • Different habitats • Need for a habitat Let’s talk about habitats of animals Look at this picture showing different habitats. You can see a grassland. What types of plants and animals do you think you will find here? It is difficult to see shelter for animals. Where do you think animals will find shelter in this habitat? Which non-living things do you think you will find in this area? Where do you think animals will find water in this habitat? Topic 4 Habitats of animals • 41 Unit 1 Animals need habitats What you know already The basic structure of a plant includes roots, stems, leaves, flowers and seeds. There are different kinds of plants. Plants need light, water and air to grow. Plants need a habitat that will provide these things. The basic structure of an animal includes a head, a tail, a body, limbs and sense organs. 1 ck Che elf mys 1.Figure 4.1 shows the basic structure of a plant. Label parts 1–6. 2 3 4 5 2.Figure 4.2 shows the basic structure of a bird. Label parts 1–9. 1 6 Figure 4.1 Basic structure of a plant 2 3 4 5 6 7 8 Figure 4.2 The body structure of a bird 42 • Topic 4 Habitats of animals 9 Life and living Lesson 1 Different habitats Each plant and animal needs a suitable place to live. The place where a plant or animal lives is called a habitat. Plants and animals are suited to live and survive in certain habitats. We say that the plant or animal is adapted to live in the habitat. There are different kinds of habitats, for example grassland, forest, river and sea. The plants found in an area determine which animals are found there, as the animals eat the plants. The different parts of the structure of an animal or plant are adapted to make the plant or animal suited to live in the habitat. For example, mammals that live on land have lungs to breathe with and legs for moving. Fish that live in water have gills to breathe with and fins to swim with. Duck that live mostly on water have lungs to breathe and webbed feet to help them swim on the water. Grassland Grasslands are large, open areas covered mainly with grasses and some trees. A grassland habitat is hot and gets rain in summer. In the winter, grasslands are cold and often get frost but no rain. Grasslands burn regularly and the plants are adapted to survive fire. Because of the fires there are very few trees in a grassland habitat. During the rainy summer, plants grow well and there is enough water and food for animals. During the dry winter there is little water and food available for animals. Word bank adapted: suited gills: the breathing organs of a fish The animals that live in a grassland habitat have to be adapted to dry winters with little food and rainy summers when food is plentiful. In a grassland habitat there are many kinds of grass-eating animals, for example impala, wildebeest, zebra and white rhinos. Topic 4 Habitats of animals • 43 Animals that eat grass are called grazers. There are burrowing animals that dig holes in the ground, for example Word bank aardvark and meerkats. Meerkats are social animals that live in groups. They burrow holes in the ground with long, sharp claws. Living underground keeps them safe from predators. When burrowing, a meerkat can close its ears to keep out dust and dirt. Meerkats eat plants, fruit, birds, eggs and small reptiles. They use their well-developed sense of smell to find food. grazer: an animal that eats grass mammal: a warm-blooded animal that gives birth to live young predator: an animal that hunts and eats other animals reptiles: cold-blooded animals that lay eggs Insects and birds are plentiful in a grassland habitat. Examples of birds found in a grassland habitat are blue crane, secretary birds and helmeted guinea fowl. Guinea fowl live mostly on the ground. They have strong claws and scratch in loose soil for food. They eat small mammals, small snakes, lizards, frogs, insects, snails, spiders and worms, as well as plant material such as fruits and seeds. There are also predators such as lions and cheetahs in a grassland habitat, because they feed on the grazers and browsers. The sand-coloured body covering of the lion acts as camouflage in the long yellow grass of the grassland so that prey cannot spot them easily. The cheetah is the fastest mammal on land. The cheetah’s excellent eyesight helps it find prey during the day. The spotted body covering makes the cheetah difficult to see in the long grass. You can see an example of a typical grassland habitat in Figure 4.3. Forest Forests are cool, shady places. Forest areas usually get rain in both summer and winter. There is no frost in a forest in the winter. 44 • Topic 4 Habitats of animals Figure 4.3 A grassland habitat Life and living Forests are moist and rarely burn. The plants in forests include large trees and smaller shrubs, ferns and ground cover that grow under the trees. The trees do not lose their leaves in winter. Because the sunlight does not reach the ground, grasses will not grow in a forest. Figure 4.4 shows a forest habitat. Figure 4.4 A forest habitat The animals that live in forests do not eat grass, but rather the leaves and fruit of shrubs and trees. Animals that live in forests have adapted to live in the trees, for example vervet monkeys. Vervet monkeys live in forests and eat the fruit and berries from plants. The vervet monkey has long limbs with hands that can grip and a long tail so that it can move through the trees. Other animals found in forests are bushpig and bushbuck. Examples of birds that live in forests are pigeons and Knysa loeries. Knysna loeries fly between trees or hop along the branches. They eat mainly fruits and berries, but sometimes also insects and earthworms. River A river is a body of moving water. Rain that runs down hills and melting ice and snow from mountains form rivers. The water in a river is usually fresh, with little salt. The bottom of a river is called the bed and the sides are called the banks. Rivers can be of different sizes and depths. The water in rivers can flow fast or slow. Some rivers run the whole year, while others dry up during the dry season. Plants and animals that live in or close to rivers need to be adapted to live in this habitat. Animals that live in rivers include fish such as bass, yellowfish and barbel. Other animals include the clawless otter, the Nile crococodile and hippos. Topic 4 Habitats of animals • 45