3 SCIENCE TEXTBOOK Name : __________________________________ Section: ________________ Roll No:__________ School : __________________________________ JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___1 / 88
How do we hone crucial learning? R REMEMBERING U UNDERSTANDING The first step of the learning process As we progress with recollecting information, involves remembering new things and we parallelly start understanding it by breaking recollecting all crucial information it down and exploring its length and breadth. such as meanings and concepts Contains the list of concepts Lesson to be covered in the lesson along with learning objectives 7 Plants Around Us Introduces the Concept List (I Will Learn) concept/subtopic in such a manner as to arouse curiosity Think among the students You find sugar, spices, flour, , oil and rice in the Introduces all new concepts to build upon the prerequisite kitchen. Where do all these things come from? knowledge/skills required to understand and apply the Remembering objective of the topic. We have already learnt about the parts of a plant. Let us learn about the Explains the aspects in detail different things that we get from plants. that forms the basis of the concept and includes Understanding elements to ensure that students are engaged The different parts of plants are useful to us in many ways. We use roots, stems, throughout leaves, flowers or fruits of plants as vegetables. The cereals and pulses which we eat are the seeds of some plants. JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___2 / 88
A APPLICATION H H.O.T.S. We begin relating what we learn to Having applied the concepts learnt, we real life situations around us, thereby extend the field of application to more applying what we have learnt. advanced and challenging scenarios. Application Connects the concept to real-life situations by giving We have seen how plant parts are useful to us. Let us see how some plant products are made using such plant parts. an opportunity to apply what the child has learnt Amazing Facts Fascinating facts and trivia Did you know a real chocolate river was made using water related to the concept chocolate and cream, for the movie Willy Wonka and the Chocolate Factory. It started smelling bad after a few days! Higher Order Thinking Skills (H.O.T.S.) Encourages the child to extend the concept learnt Inside the Lab - A to advanced application . scenarios Hands-on experience provided for creating, designing and implementing something innovative and/or useful. JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___3 / 88
Contents 1 My Hobbies...............................1 2 Family as First School...............6 3 Organ Systems.......................10 4 Skeletal System.....................14 5 Way around Our Neighbourhood......................19 6 Forms of Water........................24 Inside the Lab - A.......................29 Activity A1: Salt from Sea Water Activity A2: Create Your Compass JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___4 / 88
7 Sources of Light......................31 8 Composition of Air.................35 9 Stems and Leaves..................40 10 Uses of Animals....................46 Inside the Lab - B................................53 Activity B1: My Lava Lamp Activity B2: Leaves Leaves Everywhere 11 Food Diversity.......................55 12 Types of Houses...................61 JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___5 / 88
13 Travel with Family.................67 14 Communication without Speaking...............................71 Inside the Lab - C................................76 Activity C1: Cuisines of Different States Activity C2: Make Your Script JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___6 / 88
My Hobbies1LESSON I Will Learn Ⅸ Hobbies and their types B How hobbies are useful to us Ⅶ Choosing a hobby as a job ⅳ Parents’ hobbies My Hobbies 1 JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___7 / 88
Think Sam likes to watch movies in his free time. His sister likes photography. They enjoy doing these activities. What are such activities, that you do other than your studies, called? Remembering You go to school every day to learn new things. You play with your friends at school. What do you do after school? At home, you do homework, watch TV, play and help your parents. How do you spend your free time on Sundays and holidays? Different types of activities Some of the activities that you may enjoy doing are shown below. Guess what they are. 2 JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___8 / 88
There are different types of hobbies. They are shown in the chart given below: Understanding HOW ARE HOBBIES HELPFUL TO US? People take up hobbies to be happy. But there are other benefits of hobbies too. Some of the benefits are as follows: 1) They keep us healthy: Hobbies like exercising, sports and games keep us healthy. My Hobbies 3 JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___9 / 88
2) They help us to be creative: Art hobbies like painting and writing help us to create something new. 3) They help us to make useful things: Hobbies like knitting and pottery help us to make useful things. 4) They help us to learn new things: Hobbies like reading books helps us to learn new things. A collection of stamps and coins help us learn about different countries. 5) They teach us to work in groups: All hobbies which involve group activities teach us to work in groups. For example, games like football, hockey and so on. Group dancing also helps us learn to work in groups. Application You have learnt about the benefits of hobbies. Do all your friends have the same hobbies? One of your friends likes to play video games. Another friend likes to play badminton. Do you and your siblings like the same games Playing Playing or activities? Some of your choices may be video game badminton the same and some may be different. What could be the reason? People choose a hobby that they find interesting. Different V. V. S. Laxman people have different likes and dislikes. Therefore, different people have different hobbies. If we practise a hobby for a long time, we become good at that. Then we can carry forward that hobby also as a job. For many people, their hobbies become their jobs when they grow up. For example, V. V. S. Laxman, the Indian cricketer, was good at studies. But he became a great batsman as playing cricket was his hobby. The famous author of Harry Potter - J. K. Rowling - wrote stories as a hobby. Her hobby has become her job. Discuss your hobbies with your friends. Make a list of one another’s J. K. Rowling hobbies and what they want to become. 4 JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___10 / 88
Your friends’ hobbies What your friends want to become? Amazing Facts Did you know that collecting stamps is called the king of all hobbies? It is one of the most popular hobbies in the world. A collection of stamps Higher Order Thinking Skills (HOTS) Everyone has hobbies. What hobbies do your parents have? Did they have hobbies similar to yours when they were of your age? What could be the reason behind this? Find out. My Hobbies 5 JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___11 / 88
Family as First School2LESSON I Will Learn Ⅸ Habits and values B Habits and values differ in families Ⅶ Habits and values in your family ⅳ Good and bad habits 6 JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___12 / 88
Think Arnav was playing near his house. He saw an old lady walking with a stick. The stick fell from her hand. Arnav picked up the stick and gave it back to her. Who taught him to do so? Remembering Sleeping We live with our family members. We spend most of our time with them. So, we learn a lot from them. What do we learn from our family? Habits: These are activities that we do daily. People have different habits. Example: eating, walking, talking, sleeping and so on Eating Running Values: These are good actions and thoughts. Values help us to decide what is right or wrong. Example: respecting elders, taking care of younger ones and so on Respecting elders Taking care of younger ones Family as First School 7 JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___13 / 88
Understanding Some habits that we learn from our family members are: • the type of food we like to eat • the way we eat • table manners • the time we go to bed and get up • how loudly or softly we talk or laugh How do we learn different values from our family? Learning table manners from parents Being kind and helpful: What happens when you are sick? Your family takes care of you. Respecting others: Your parents talk to elders with respect. They listen to what the elders say. Being disciplined: Your parents get up on time and do the household work. They help you get ready for school. Then they go to work. They have taught you to get up early and not be late for school. Does your family behave in the same way as your friends’ families? No, you will find differences. Habits and values within families are different. In some families, the family members: • touch the feet of elders • stand up when elders enter • keepfootwearoutsidethehouse • eat meals and celebrate festivals together Praying before meal • pray before meals and so on Do your family members follow any of these practices? 8 JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___14 / 88
Application You have read about the habits and values we learn from our families. What are the good habits and values that you have learnt from your family? Who is the family member you respect the most? Why do you respect him/her? Whom do you respect other than your family members? Some people you respect are the school principal, teachers, helpers, drivers, cleaners and so on. All of them help to run the school. Do you think all that we learn from others can be good for us? Do your parents or teachers say that you have learnt some bad habits? Fighting and shouting Throwing garbage around How can we make sure that we learn only good things from others? Find out with the help of your teachers and parents. Amazing Facts Did you know having breakfast is a healthy habit? Children who have breakfast everyday can study and play better than others! Higher Order Thinking Skills (HOTS) Write a letter to a family member. Talk about the good habits and values you have learnt from that person. Thank him or her for it. Also, write about any bad habits he or she should quit. Family as First School 9 JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___15 / 88
3LESSON Organ Systems I Will Learn Ⅸ Organs inside the body B Different organ systems and their organs Ⅶ Effect of daily activities on organ systems ⅳ Position of different organs inside the body JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___16 / 88
Think When we breathe in, we take in air. Where does this air go? It goes inside our body. Let us find out what is inside our bodies. Remembering We have some special body parts. These body parts that help us to do special and important work are called organs. We see some organs from outside. But there are some organs that are inside the body. We cannot see them. ORGANS INSIDE OUR BODY Food pipe: It is a tube, which leads from the mouth, through the throat to the stomach. Food pipe Stomach: It is a sack-like organ. When we eat food, it goes into the stomach through the food pipe. Windpipe: It is a tube that connects the throat to the Stomach lungs. It is also called trachea. Lungs: There is a pair of lungs in the chest. Food pipe and Stomach Windpipe Heart: It is located a little to the left of the middle of our chest. It is about the size of our fist. Lungs Lung Kidneys: We have a pair of kidneys. They are bean-shaped. Brain: It is present inside the head. Some organs inside our body form a group Heart to do specific tasks. Such a group of organs is called an organ system. There are many such organ systems. Kidneys Brain Organ Systems 11 JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___17 / 88
Examples of some organ systems are digestive system, circulatory system, skeletal system, muscular system and so on. Understanding SOME IMPORTANT ORGAN SYSTEMS Food pipe Stomach Our body has many organs and organ systems. They Intestines work together to carry out different tasks. Digestive system helps to take in food through our mouth and foodpipe. In our stomach, food is broken down to make it easy to digest(just like a mixer- grinder). The digestive system consists of mouth, foodpipe, stomach and intestines. Respiratory system helps in breathing. The organs of this system are the nose, the windpipe and the lungs. Heart Digestive system Blood Circulatory system sends blood to all parts of vessels the body. The heart is the most important organ in this system. It pumps blood to all the parts of the body just like a water pump. Blood flows through the blood vessels(thin tubes like water pipes). Our brain controls all activities of our body. It helps us think and learn. The brain is a part of the nervous system. Circulatory system 12 JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___18 / 88
Application Now, you know about the different organ systems and how they work. Can we control all these organs? We cannot directly control the organs inside our body. The brain works even when you are sleeping. You breathe continuously when you are running, eating or sleeping. Is the breathing faster or slower when you are doing these activities? The heart beats continuously. Does the heart rate remain the same or is it different? Amazing Facts A child’s heart beats faster than an adult’s. Your heartbeat changes depending on the type of music you are listening to. Higher Order Thinking Skills (HOTS) Make an outline of the human body on a cardboard and cut it out. Draw the different organs inside our body on a piece of paper. Colour them. Cut them out. Can you place these organs correctly on the cut out of the body? To do this activity, you will need: • a piece of cardboard • a piece of paper • pencil • crayons • scissors • gum Cut out of the body and organs Organ Systems 13 JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___19 / 88
Skeletal System 4LESSON I Will Learn Ⅸ Skeletal system B Functions of the skeletal system Ⅶ Keeping our bones healthy ⅳ Skeletal system in other animals 14 JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___20 / 88
Think Asif fell while cycling. He hurt his leg. His mother took him to the doctor. Doctor told them to get an x-ray picture of the leg. Do you know what an x-ray picture tells us? An x-ray picture of the leg Remembering Hold your wrist. Do you feel Skull something hard inside? It is the bone. Our body has many such Rib cage bones. Backbone (Vertebrae) At birth, we have around 300 bones. As we grow, some bones fuse and join. Adults have 206 bones. Joints are places where two bones meet. Example: knee, elbow All the bones in our body together form the skeletal system. IMPORTANT PARTS OF THE SKELETAL SYSTEM Skull: Bones in the head form Human skeletal system the skull. Ribs: Bones around the chest form the ribs. The ribs join in front and back, to form a rib cage. Skeletal System 15 JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___21 / 88
Backbone: Many small bones join to form a rod-like structure called backbone. It runs down from the neck to the lower back of our body. It is also called the vertebrae. Understanding FUNCTIONS OF THE SKELETAL SYSTEM 1) The skeletal system gives shape and support to our body. Example: Skull bones give shape to our head and face. The backbone helps us to stay erect. Imagine how your body will be without a backbone! Bones store minerals inside them. These minerals make them strong enough to support our body. 2) It protects the organs inside our body. For example, the rib cage protects the lungs and the heart. The skull protects the brain from any injury. Skull Rib cage Brain Lung Heart Skull Rib cage 3) The skeletal system helps us to move. Joints help our body to twist and turn. For example, leg joints help us to walk and run. Application HOW CAN WE KEEP OUR BONES STRONG AND HEALTHY? Healthy food: Vitamins and minerals like calcium make our bones strong. So we must eat food items which contain these nutrients. Leafy vegetables, pulses and milk products are rich in calcium and vitamins. 16 JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___22 / 88
Leafy vegetables Pulses Milk products Good posture: We should always sit straight in the right posture to keep our bones strong. Exercise and play: Playing and exercising regularly keeps our bones strong and healthy. WHAT IS A FRACTURE? Good and bad postures Sometimes bones get hurt during accidents or by falling hard on the playground. In such cases, the bones may crack or break. This crack or break is called a fracture. How can we know if there is a fracture in our bone? For Fracture this, an x-ray picture is taken. They help the doctor to see the fracture in the bones. Once the doctor knows where the break is, he or she will put a plaster around it. It keeps the bone in proper position and helps in healing. Plaster Plaster helps to heal the fracture Skeletal System 17 JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___23 / 88
Amazing Facts The smallest bone in our body is found in our ear. This bone is called stapes. The longest bone in our body is the thigh bone or femur. Femur Higher Order Thinking Skills (HOTS) You have learnt that humans have a skeletal system Shell inside their body. Some animals have an exposed skeletal system. Have you seen a tortoise? It has a hard cover/shell on the body. Shell Tortoise of a tortoise is an example of exposed skeletal system. Make a list of animals having such shells. Earthworm You must have seen many creepy crawlies like earthworms around your house. Do they have skeletal systems? 18 JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___24 / 88
Way around our 5LESSON Neighbourhood I Will Learn Ⅸ Directions and sub-directions B How to identify directions Ⅶ Mapping our neighbourhood ⅳ Use of a compass Way around Our 19 Neighbourhood JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___25 / 88
Think Can you help the puppy to find its way home? To reach the house the dog needs to know where to take the turns. In the same way we also need to know our way to travel in our neighbourhood or inside our school. How do we find our way? Remembering What do we need to know to go to any place? We should know the address and where it is located. When we tell someone how to go to a place, we give directions. While giving directions, we use words like left, right, straight and so on. We use these words in relation to a landmark. Turn left Turn right Go straight Go past Cross ahead DIRECTIONS AND SUB-DIRECTIONS We also give directions using the four main directions – north (N), east (E), west (W) and south (S). There are also four sub-directions that lie between these main directions. They are north-east, north- west, south-east and south-west. 20 JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___26 / 88
North North - North - west east West East South - South - west east South Directions and sub-directions Understanding How do you know which is the North and which is Finding directions the East? Let us do an activity to find directions. Stand facing the Sun when it rises. That direction is the East. Open your arms as shown in the picture. The direction behind you is the West. Your right-hand shows the South. Your left-hand shows the North. These directions and sub-directions help us to know places in our neighbourhood. They also help us to read maps of our city, district, state and so on. Application To read a map, you need to know the directions that you have learnt. A map is given below. It shows a ‘house’. Riya lives in this house. Her house is east- facing. She wants to go to the post office to post a letter to her friend. Let us help Riya. Way around Our 21 Neighbourhood JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___27 / 88
Map Since Riya’s house is east-facing, she faces the East when she steps out. The directions are as follows: • Step out of the house and go to the road on your left. • Turn west. • Walk westward on the road. • Turn left towards the South at the end of the road. • The post office is at the corner of the road. Is there any other way to reach the post office? Discuss with your friends. Amazing Facts An interesting way of remembering directions is: Never Eat Slimy Worms N = North, E = East, S = South, W = West 22 JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___28 / 88
Higher Order Thinking Skills (HOTS) One more way of finding directions is to use a compass. It is a device used to find directions on the surface of the Earth. It has a needle which always points towards north-south direction. It is mainly used in ships to understand the direction. Compass Way around Our 23 Neighbourhood JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___29 / 88
6LESSON Forms of Water I Will Learn Ⅸ Forms of water B Water cycle Ⅶ Changing water forms around us ⅳ Salt from sea water 24 JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___30 / 88
Think While going to school, Aslam saw a roadside puddle. But while coming back from school, he found that it had dried up. How did the water disappear? Puddle Remembering We hang clothes out in the sun to dry. Why do wet clothes dry after some time? Heat from sunlight changes the water in the clothes Clothes hung in the sun to water vapour. It moves out of the clothes and the clothes dry. We can also see water change into vapour when we boil water. Water vapour When cooled, water vapour changes into water. Very cold conditions change water to ice. We find ice inside refrigerators and in very cold places around the world. Ice Ice-covered land Forms of Water 25 JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___31 / 88
On heating, ice melts to form water. Melting ice Water Let us now learn about the three forms of water. What are the differences between water, water vapour and ice? Ice has a shape. It doesn’t flow. Water flows and doesn’t have a shape of its own. It takes the shape of the vessel. Water always flows downwards. Water vapour has no shape. It always moves upwards and mixes with the air around. All three forms of water have no colour, smell and taste. Understanding We get water from rain. The rainwater gets collected in water bodies like rivers, ponds, lakes and so on. Some water goes down the soil and is stored underground. During daytime, heat from the Sun changes the water of the water bodies into vapour form. The water vapour thus formed goes upwards and cools down. It forms small water droplets. These water droplets (with other things) form clouds in the sky. Inside the clouds, the water droplets combine to form big drops. When the water drops in the clouds become too heavy, they fall as rain. During winter, in some very cold places, water changes to ice and snow. Thus, water changes its form and always moves from the water bodies to the clouds and back. This movement is called the water cycle. It makes water available to all living things. 26 JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___32 / 88
Clouds Rain Water vapour Water cycle Application We have read that clouds give us rain. How do rain clouds look like? Rain clouds are dark in colour. They are heavy and filled with water droplets. Cloud Rain cloud Why is it that other clouds do not come down as rain? Find out. Have you ever been to a sea-shore? There we sweat a lot. Do you know the reason for this? In sea-shores, the air is filled with water vapour. So the water in our sweat doesn’t get changed into vapour easily. Sea-shore Forms of Water 27 JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___33 / 88
Have you seen dew drops on leaves in the morning? Where do they come from? Some water vapour is always present in the air around us. It cools down when it touches any cold surface. This is the reason why we see water droplets on a glass of cold water. We learnt that wet clothes dry due to that heat from the Sun. How do wet clothes dry when we keep them indoors? In monsoon, clothes dry with difficulty. Why is it so? Water droplets on a glass of cold water Amazing Facts Fog is a cloud that appears very close to the ground. Fog Higher Order Thinking Skills (HOTS) Do you know that the common salt is prepared from sea water? Sea water contains a lot of salt. So it is unfit for Sea water collected in ponds drinking. This salt can be separated out. For this, the sea water is collected in open ponds. Due to the heat from the sunlight, the water changes into the vapour form. The salt which remains in the ponds is collected and purified to be used as the common salt. 28 JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___34 / 88
Lab Activity A Please do not try these activities on your own. Make sure you do these activities only with the help of a teacher or an adult. Activity A1: Salt from Sea Water In the lesson ‘Forms of Water’, we learnt that water exists in three different forms. Let us see how we get salt from sea water due to Sea water collected in ponds changing forms of water. You will need: Salt, some tap water, a saucepan, spoon, stove, tray and a black plastic sheet You need to: 1) Add two cups of water to the pan. Place it on the burner. Let the water boil. 2) Add salt to the hot water in the pan. Mix it well with a spoon. Salt dissolves faster in hot water. Continue adding salt until it no longer dissolves in hot water. Eventually, you’ll reach a point at which the salt won’t dissolve anymore, no matter how hot the water is. When you reach that point, turn the stove off and let the water cool slightly. 3) Spread the black plastic sheet inside the tray. 4) Pour the water from the pan to the tray. 5) Keep the tray out in the sun for two days. (The location should be chosen wisely to prevent the Black plastic paper and tray setup from any external damage.) The water will change into water vapour. This will leave behind crystals of salt in the tray. They are small and shiny. Salt is prepared from sea water in a similar way. Sea water changes into water vapour during summer, leaving behind salt. Inside the lab - A 29 JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___35 / 88
Activity A2: Create Your Compass The magnetic compass is used to detect/find out directions: north, south, east and west. It has a magnetic needle that points to the north. You can easily make your own compass. You will need: Compass A bar magnet, needle, cork disc, cup/bowl/glass, pair of pliers, water You need to: 1) Rub a magnet over the needle about twenty times. Magnet Always rub in the same direction. Needle 2) Now cut off a small portion from one end of the cork, about ¼ -inch thick, making a small cork disc. This step should be done with the help of the teacher. 3) Put the cork disc on a flat surface. Carefully push the needle through the side of the disc as shown in the picture. Use the pair of pliers to push the needle. This step should be done only with the help of the teacher. 4) Fill a deep cup, drinking glass or bowl at least half with water. 5) Put the cork disk with needle, from step 3, on the surface of the water. Try to keep the disc floating in the centre of the water, away from the sides of the cup. 6) Place your compass on a flat surface and watch what happens. What does the needle do? When it stops moving, which direction does it point towards? 30 JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___36 / 88
7LESSON Sources of Light I Will Learn Ⅸ Natural and artificial sources of light B Discovery of fire as a source of light Ⅶ Electricity as a source of light ⅳ Light as heat Sources of Light 31 JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___37 / 88
Think Nowadays, we see electric bulbs everywhere. What did your grandparents use to light up their homes when they were young? Remembering Our eyes help us to see the things around us. But why are we unable to see in the dark? This is because our eyes can help us to see things only in the presence of light. Where do we get light from? We get light from two different sources: a) Natural sources b) Artificial sources or man-made sources Natural sources: These sources include heavenly bodies like the Sun and the stars. The stars The Sun Artificial sources: The artificial sources of light are made by human beings. They include electric bulbs, kerosene lamps, oil lamps, candles and so on. Electric bulb Kerosene lamp Oil lamp Candle 32 JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___38 / 88
Understanding In ancient times, there were no artificial sources of light. Human beings could only hunt and gather food during the day time. Then, humans discovered fire by rubbing flint stones. This helped them to get light even Flint stones Firewood after sunset. They could also guard their caves from dangerous animals with the help of fire. Earlier, humans would burn firewood for light. Time went on. Then they started using oil lamps, candles and lanterns like we do today. After the discovery of electricity, humans started using Artificial light sources electric lamps as a light source. then and now Application What type of light sources should we use? We should try to use the natural source of light, that is Solar panels sunlight, to the maximum. This is the cheapest source of light. We can use solar panels to capture light and convert that to electricity. This electricity can be used to light our homes in the night. Artificial sources of light like electric bulbs need electricity to give out light. This electricity is limited. So, we should use light sources which use less electricity. For example, LED bulbs, tube lights and CFL bulbs. LED and CFL bulbs Sources of Light 33 JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___39 / 88
Moreover, we should switch off the lights when not in use. Some artificial sources of light cause harm to the environment. For example, kerosene lamps give out smoke. We should try to avoid use of such sources. Kerosene lamp Amazing Facts Have you seen fireflies? They are insects giving out light from their bodies. Some aquatic animals like jellyfish also give out light. Firefly Jellyfish Higher Order Thinking Skills (HOTS) Many light sources also give us heat. We use fire for cooking as it provides heat. We can use sunlight for heating water and cooking food with the help of solar heater and solar cooker. Solar water heater Solar cooker 34 JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___40 / 88
Composition of Air8LESSON I Will Learn Ⅸ Air is a mixture B Sources of components of air Ⅶ Air pollution ⅳ Firecrackers in the air Composition of Air 35 JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___41 / 88
Think Arjun woke up early in the morning to go to school. He found that the air was fresh and cool. When he came back from school in the afternoon, he felt the air was not so fresh and cool. Do you know why? Remembering We know that air is all around us. Air is a mixture of different gases. Gases are substances that can move around freely. Gases do not have any shape of their own. They can fill any available space of any shape. Oxygen, carbon dioxide and nitrogen are the main gases present in the air. Air is mostly made up of nitrogen and oxygen. Carbon dioxide and some other gases are present in smaller amounts. Air also contains water vapour, the gaseous form of water and some dust. Clean air does not have any smell or colour. Understanding We have learnt that air contains different gases. Let us find out the sources of these gases. We all need air to breathe. All animals breathe in oxygen and give out carbon dioxide. At the same time, plants take in carbon dioxide from the air to make their food. They give out oxygen during this process. 36 JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___42 / 88
Carbon dioxide Oxygen Sources of oxygen and carbon dioxide in air In this way, the levels of oxygen and carbon dioxide in the air are maintained. What will happen to this balance, if we cut trees unnecessarily? We know that water vapour in the air comes from different water bodies. Once the air gets filled with water vapour, it changes into water droplets and falls as rain. Application Sometimes the air gets filled with smoke and dust. The presence of such harmful substances in the air is called air pollution. Substances which make the air dirty(or pollute the air) are called pollutants. Let us find out the sources of these pollutants. When we burn something such as firewood or kerosene lamp, it gives out smoke. Smoke from vehicles and factories also pollute Firewood Kerosene lamp the air. Vehicles also blow up dust in the air. Carbon dioxide is useful at very low levels. But when its amount increases above normal levels, it becomes a pollutant. Any colour or bad smell of air Vehicles Factory shows air pollution. Polluted air is unhealthy. It may damage our lungs and eyes. It makes us feel tired and sick. Composition of Air 37 JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___43 / 88
If the air is polluted, we should wear masks. Masks filter the air and allow only clean air to enter our nose. How can we keep the air clean? 1) Plant trees: Plants absorb carbon dioxide and give out oxygen. They help to maintain the Child wearing a mask air clean and healthy. So, we feel fresh when we are in a field, garden or a forest. It is, therefore, important to plant trees. 2) Use smoke-free lamps and stoves: We should avoid using cooking stoves and lamps which give out smoke. 3) Stop burning garbage: We should not burn garbage in our neighbourhood. Plastics in the garbage give out harmful gases on burning. 4) Use well-maintained vehicles: Some vehicles that are not maintained or are old give out harmful gases. Amazing Facts As we go higher, the level of oxygen in the air decreases. So, the people who climb mountains carry oxygen cylinders with them. Higher Order Thinking Skills (HOTS) Crackers People burst firecrackers(crackers) on festivals and special occasions. Do you think crackers are good for the environment? Crackers are made up of chemicals which catch fire easily. They make a lot of noise. They also add harmful smoke to the air causing 38 JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___44 / 88
air pollution. The people who make crackers in factories suffer skin and lung problems. It is dangerous to work in places People who make crackers where they are made or stored. Still, at some places, even small children are forced to work in cracker factories. We should, therefore, stop bursting crackers. Composition of Air 39 JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___45 / 88
9LESSON Stems and Leaves I Will Learn Ⅸ Different types of stems and leaves B Functions of stems and leaves Ⅶ Uses of stems and leaves ⅳ Shedding of leaves JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___46 / 88
Think Nitin’s teacher showed him four leaves. She asked him to find the differences between them. What differences will Nitin find? Remembering You have learnt about various types of plants. You have also learnt that a plant has different parts. Now, let us learn about the stems and leaves of plants in detail. THE STEM Tree trunk The stem is usually seen above the ground. It is generally green when young and later becomes woody and dark brown. The stem is different in different types of plants. The stem of a big tree is called the trunk. Stems may be with branches or without branches. For example, mango trees have branches but coconut trees have no branches. Stem with branches Stem without branches Stems and Leaves 41 JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___47 / 88
Stems are usually erect, but in some plants they can be creeping or twisted. For example, pumpkin plants have creeping stems. Creeper stem of In some plants such as the Thorns of Hairs on pumpkin rose stem tulsi stem rose plant, we can see thorns on the stems. In some plants, stems are covered with small hairs. Some stems are smooth. Example: bamboo tree Some stems are rough. Example: mango tree Bamboo stems Rough stem or bark of a mango tree We have learnt about the different types of stems in plants. Now, let us learn about leaves. THE LEAVES The leaves are important parts of plants, just like the stems. They are of different size, shape and colour. They are arranged in different ways in different plants. Let us take a look at some leaves. Banana plants have big leaves and tulsi plants have small ones. Banyan trees have heart-shaped leaves. Lotus plants have round ones. Some leaves have toothed edges. Different types of leaves Example: neem Some leaves have a special smell. Example: tulsi 42 JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___48 / 88
Understanding We have learnt about different types of stems and leaves. But, why do plants need stems and leaves? Let us see how stems and leaves are helpful to plants. FUNCTIONS OF STEMS 1) The stem allows the plant to stand upright and holds up the branches and leaves. It holds the leaves in such a way that they can get maximum sunlight. 2) The stem carries water and nutrients from the roots to the Trunk helps the tree leaves. It carries food prepared in the leaves to the to stand upright different parts of the plant. 3) Some stems store food for the plant. Example: sugarcane FUNCTIONS OF LEAVES Sugarcane Plants need food to live. Leaves make food for the plant. They also help plants to breathe. How do leaves make food? To make food, leaves need sunlight, water and carbon dioxide gas. They take carbon dioxide gas from the air. Water from the roots reach the leaves through the stem. Using sunlight, leaves combine water and carbon dioxide to make food. So, they are called ‘kitchen of the plant’. Leaves are also called ‘food factories of the plant’. Application We have learnt about the functions of stems and leaves. Now, let us see how we use stems and leaves in our day-to-day life. Stems and Leaves 43 JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___49 / 88
USES OF STEMS Some stems are used: • as food. Potato and onion are examples. Sugarcane stem is used to make juice, sugar and jaggery. • to make furniture as they are hard and strong. Teak and mahogany are examples. • to make medicines. For example; tulsi, neem • to make useful things like rubber and jute. The milky juice from the stem of the rubber tree is used to make rubber. The stem of the jute plant is used to make jute. We make ropes and bags using jute. USES OF LEAVES Some leaves are used: • as food. Leafy vegetables such as spinach, parsley are some examples. Leaves of tea plant are used to make tea. • as spices in cooking. For example; bay leaves, coriander Bay leaves • to make medicines, like the leaves of tulsi and neem. • to cook and serve food. Examples; turmeric leaf, banana leaf • as decorations during Cooking food using a leaf Serving food on a leaf festivals and special occasions. Amazing Facts The green colour of leaves is due to a substance called Chlorophyll. Leaves turn brown due to a substance called Tannin. Tannin also gives the colour to your tea. 44 JSNR_BGM_1010021_Alpine-G3-FoundationMax-Science-FY_Text.pdf___50 / 88
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