CO MPASS SERIES science textbook part - 1 3 Name: Learn@Home Sec�on: Roll No.: School:
Preface ClassKlap partners with schools, supporting them with learning materials and processes that are all crafted to work together as an interconnected system to drive learning. Our books strive to ensure inclusiveness in terms of gender and diversity in representation, catering to the heterogeneous Indian classroom. ClassKlap presents the Compass series, designed specifically to meet the requirements of the new curriculum released in November 2016 by the Council for the Indian School Certificate Examinations (CISCE). Guiding principles: The 2016 CISCE curriculum states the following as its guiding principles for Science: Theme-based learning Relating science learning to the daily-life experiences of students Focus on skill/process development Providing opportunities for knowledge construction Infusion of environmental issues into the content Each of these principles resonates with the spirit in which the ClassKlap textbooks, workbooks and teacher companion books have been designed. The ClassKlap team of pedagogy experts has carried out an intensive mapping exercise to create a framework based on the CISCE curriculum document. Key features of ClassKlap Compass series: Theme-based content that holistically addresses all the learning outcomes specified by CISCE curriculum Opportunities for experimentation, analysis and synthesis of ideas and concepts Exposure to locally relevant environmental problem solving Focus on science-specific vocabulary building Promotion of participatory and contextualised learning through the engagement of all relevant stakeholders in the learning process All in all, the Compass Science books aim to enhance the learning of science, development of scientific temper and curiosity towards scientific activities along with the inculcation of healthy habits for environmental protection. – The Authors
Textbook Features • Use of simple, age-appropriate language • Activity-based approach to learning • Use of infographics and pictures to explain concepts and terms • Focus on subject-related vocabulary building I Think I Will Learn About • Introduces the concept/ • Lists the key learning subtopic in a manner as to outcomes of the lesson arouse curiosity and interest among students ? In-text Questions Pin-Up-Note • Oral discussion questions to check for learning and to • H ighlights the key points or gauge the understanding definitions level of the child Connect the Dots A Be Amazed • Fosters interdisciplinary • F ascinating facts and trivia thinking by connecting other related to the concept subjects to an aspect of the taught concept Inside the Lab A Note to Parent • Hands-on experience • E ngaging activities to be done provided for creating, at home along with parents to designing or implementing reinforce the concept something innovative and/or useful based on the concept learnt
Contents 1 The Circulatory System ����������������������������������������������������������������������������������1 2 The Skeletal System ����������������������������������������������������������������������������������������8 3 Healthy Food��������������������������������������������������������������������������������������������������15 4 Pollination ������������������������������������������������������������������������������������������������������24 Inside the Lab – A �������������������������������������������������������������������������������������������������30 Activity A1: Hear Your Heartbeats Activity A2: Germ Charades 5 Reproduction in Plants ���������������������������������������������������������������������������������32 6 Solids, Liquids and Gases ����������������������������������������������������������������������������37
1Lesson The Circulatory System I Will Learn About • the human circulatory system. • parts of the human circulatory system. • the structure and functions of the organs in the circulatory system. • the process of circulation. • ways to keep the circulatory system healthy. I Think Raju tripped while running. He hurt his knee, and it bled. Have you ever thought why we have blood inside our body? We have learnt earlier that our body needs oxygen and nutrients. We take in oxygen through our respiratory system. Our digestive system helps to break down food and absorb all nutrients. How do oxygen and nutrients reach all other parts of our body? Let us find out. The human circulatory system When we need to move a thing from one place to another, what do we do? We move it with the help of our hands or a vehicle. In the The organ system that same way, our body has a system to move things around. transports different This system carries oxygen and nutrients, amongst other substances within our things, to all parts of the body. It also removes waste body is called the materials such as carbon dioxide from the body. This circulatory system. system is called the circulatory system. 1
Parts of the human circulatory system The human circulatory system has three important parts. 1) H eart: It is a muscular organ whose size is about that of Heart our fist. It is located a little to the left of the middle of our chest. It is protected by the ribcage. Blood vessels 2) B lood: It is a red-coloured liquid that circulates throughout the body. It carries oxygen, nutrients and waste material from one organ to the other. 3) B lood vessels: They are thin The Heart, blood Human circulatory tube-like structures that form a and blood vessels system network in our body. There are form the circulatory three types of blood vessels: system. arteries, veins and capillaries. ? Name the different types of blood vessels. The structure and functions of the organs in the circulatory system Let us now learn about the structure and functions of different organs in the circulatory system. 1) Heart: It is a pear-shaped Left atrium organ consisting of four Right atrium chambers. The two, upper Left ventricle chambers are called the Right ventricle atria(singular – atrium) or auricles. The atria are the chambers that receive the blood coming to the heart from the rest of the body. The two, lower chambers are called the ventricles. The heart has a left ventricle and a right ventricle. They send blood to the body and lungs. ? Name the two lower Structure of the human heart chambers of the heart. 2
d The atria and ventricles work as a team. The atria get filled with blood, and then send it into the ventricles. The ventricles then squeeze and pump the blood out of the heart. While the ventricles contract (decrease in size by the action of squeezing), the atria refill with blood from different parts of the body and get ready for the next contraction. The heart works like a pump to keep the blood continuously flowing through the network of blood vessels. The rhythmic pumping of blood by the heart is called the heartbeat. Doctors use an instrument called the stethoscope to listen to our heartbeats. When we place our fingers on the left wrist, we feel a light pumping movement. This is called a pulse. For an adult human being, the normal pulse rate may vary from 60 to 100 beats per minute. 2) Blood: It flows inside our body through a network of blood vessels. Blood works like a carrier. a) It carries oxygen from the lungs to other parts of the body. It also collects carbon-dioxide from the body and takes it back to the lungs. b) A fter the process of digestion, blood carries nutrients absorbed from the digested food in the intestines to other parts of the body. c) I t also absorbs the waste materials from different parts of the body and takes it to the excretory system. d) B lood helps in maintaining the temperature of the body and thus, prevents the body from becoming too hot or too cold. e) S ome of the components present in the blood protect the body from disease- causing germs. Whenever harmful germs enter our body, these components attack and kill them. We will learn about these components in higher classes. Be Amaze A Although blood in all individuals looks alike, the type of blood is not the same. There are four different types of blood – A, B, AB and O. Find out from your parents what your blood type is. 3) Blood vessels: They are tube-like structures spread through out our body. They carry blood to different organs and parts of our body. They are of three types: arteries, veins and capillaries. Together they are called blood vessels. They form a network inside our body. The Circulatory System 3
The blood vessels that carry blood away from the heart are called arteries. The largest artery in our body is called the aorta. It is the main artery leading out of the heart. Another important artery is the carotid artery. It carries blood from the heart to the brain. Blood vessels that carry blood back to the heart are called veins. An important vein that carries blood from the upper portion of the body to the heart is the superior vena cava. The vein that fetches blood from the lower portion of the body to the heart is the inferior vena cava. Capillaries form a network of tubules between the arteries and the veins. Let us learn how the continuous movement of nutrients, oxygen and carbon- dioxide take place in the various parts of the body with the help of the circulatory system. The process of circulation 1) Due to the contracting and relaxing movements of the walls of the heart, blood flows in and out of the heart. 2) Arteries carry blood leaving the heart. They branch out into smaller arteries, which further branch out into narrow capillaries. These capillaries reach all parts of our body. The blood in the capillaries delivers oxygen and nutrients to the various parts of the body and also absorbs the waste products. 3) The capillaries then join the veins. Veins carry blood to the heart. Then, it is pumped to the lungs. Here, the oxygen from the air that we have breathed in gets mixed with the blood and flows back to the heart from the lungs. This blood is then pumped to the different parts of the body. Our body cannot survive without oxygen for long. So, the circulatory system works non- stop to supply oxygen. Imagine yourself doing the same work non-stop for years. What will happen? You will get tired and weak after some time. But our circulatory system works continuously. Just imagine how strong and hardworking our heart is. We need to take care of it so that it does not become weak. Let us find out about the different ways of keeping our heart healthy. Ways to keep the circulatory system healthy So far, we have learnt about the important functions of the circulatory system. How can we take care of our circulatory system and keep it healthy? 4
1) Exercise: We need to exercise to keep our heart healthy and strong. Activities such as brisk walking, jogging, swimming, cycling and dancing help to keep the heart muscles strong. We must avoid sitting for a long time while watching TV, playing computer/mobile games or doing homework. We should get up from our seat and move and stretch every 20 minutes. Exercises 2) Healthy food: We need to have a balanced diet and avoid eating oily food. Too much oily food is harmful to the heart and blood vessels. Oil absorbed by blood will gets deposited in our blood vessels. So the heart will need to work harder to pump blood. Healthy food The Circulatory System 5
3) Yoga, deep breathing and meditation: Tadasana Dhanurasana Doing yoga also keeps the heart healthy and improves blood circulation. Performing a variety of yoga postures, gently stretches and exercises the muscles. There are a few asanas that can help in improving the health of the heart. For example, tadasana (mountain pose), dhanurasana (bow pose) and other such asanas. Deep breathing can help to calm our mind and ease our stress. It also improves the function of the lungs. Meditation helps to calm our mind and reduce stress. It is often combined with yoga. Connect the Dots English Fun Find the noun form of the following verbs using a dictionary: a) circulate: _________________________________________________________________ b) locate: ___________________________________________________________________ Maths Fun Consider that our heart pumps 50 ml blood in one beat. If a heart beats 70 times in a minute, how much blood will it pump in two minutes? Blood pumped by a human heart in one beat = 50 ml Number of heartbeats in a minute = 70 Thus, the number of heartbeats in 2 minutes = 2 × 70 = ____________ Hence, the blood pumped by the heart in 2 minutes = The number of heartbeats in 2 minutes × 50 = _______________ × 50 = ________________ ml 6
A Note to Parent Discuss with your child the first-aid help they can give to any person with a small cut or wound. Make him/her familiar with some home-made remedies like turmeric powder, neem leaves or aloe vera that are used to treat minor injuries. First-aid measures to be taken in case of a cut or a wound 1 Clean the cut or the wound 2 Try to stop the bleeding by with warm water and soap applying pressure on the wound with a clean cloth 3 Apply medicine to the 4 Cover the wound with a wound to reduce the clean bandage chance of infection The Circulatory System 7
2Lesson The Skeletal System I Will Learn About • the human skeletal system. • parts of the skeletal system. • functions of the skeletal system. • ways to keep our bones and muscles healthy. I Think Asif fell while cycling and hurt his leg. His mother took him to a doctor. The doctor said that there might be an injury to a bone. Do you know what a bone is? The human skeletal system Hold your wrist. Do you feel something hard inside? It is a bone. Our body has many such bones. At birth, we have around 300 bones. As we grow, some bones fuse and join. Adults have 206 bones. All the bones in our body together form a framework of the body. This framework is known as a skeleton. The skeleton supports the skin, muscle and all the organs that are inside the body. If we did not have a skeleton, the body would be flat. The human skeletal system 8
The skeleton supports our body and gives it a definite The skeletal system is shape. The bones in our body together form an organ made up of bones. All system known as the skeletal system. the bones in our body ? How many bones do we have at birth? tcoaglleetdhethrefosrkmelaetforanm. ework Parts of the skeletal system Skull and the jaws: The bones in the head together form the skull. The skull is a rounded, hollow skeletal structure in the head. The upper part of the skull that covers the brain has eight bones. These bones are fixed and immovable. The face has 14 bones. The lower jaw bone is the largest and strongest facial bone. It is U-shaped and movable. It is attached to the upper jaw. The lower and upper jaws have teeth. Our ears also have bones. Upper jaw There are three bones in each ear. The smallest bones in the body are those in the ear. Lower jaw Be Amazed Skull A The smallest bone in our body is found in our ear. This bone is called the stapes. Backbone: Many small bones in our back join to form a rod-like structure called the backbone. It is not straight, but slightly curved. It helps to support the body, and helps a person to move and bend. It is also known as the vertebral column or spine. The spine has 33 bones. Each individual bone is called a vertebra. The backbone or the spine stretches from the base of the skull to the lower back of our body. Ribcage: It is a bony cage in the chest region. It is made of curved bones called ribs. 12 pairs of such ribs form the ribcage in our body. A long bone called the sternum holds the ribs in the front. The last two ? How many bones join to form the backbone? Backbone The Skeletal System 9
pairs of ribs are called the floating ribs as they are not attached to the sternum. At the back, the backbone holds the ribs together. Bones of the arms: Each arm has Sternum three main bones and some small Ribs bones. The uppermost bone is the humerus that lies between the Ribcage shoulder and the elbow. Two other bones make the lower arm. They are positioned in between the elbow and the wrist. Bones of the legs: The Thigh bone Humerus upper leg consists of a (femur) Elbow bone called the thigh bone or the femur. It is Knee Wrist the longest bone in our body. It is joined to the two bones of the lower leg at the knee. Girdles: These are ring- Bones in arms and legs like structures made of bones. There are two girdles in the human body – the shoulder girdle and the hip girdle. Joints: We have learnt that our Shoulder girdle Hip girdle skeletal system is made up of different types of bones. These bones join each other at certain points called joints, such as the knee, elbow and other such joints. Bones at the joints are connected to each other with the help of band-like structures called ligaments. At the joints, the surfaces of the bones are covered with a substance called ? Name the longest bone in the cartilage. Cartilages can bend. the human body. They protect the bones from getting damaged. Our nose and ears also have cartilages present in them, which make them flexible. 10
The joints are of two types: movable joints and immovable joints. Immovable joints are those which cannot move. They are fixed. These joints are found in the skull. Movable joints can move. They are of various types. Following are some examples. a Ball and socket joint: This type of joint b Hinge joint: This type of enables movement in all directions. The joint joint allows only back and has a ball-shaped end of one bone that fits forth movements. Knees, into a cup-shaped socket of another bone. elbows, fingers and toes are For example, shoulder and hip joints. examples of the hinge joint. Socket of hip bone Femur Head of femur (thigh bone) Ball and socket joint Hinge joint c Pivot joint: This type of joint allows d Gliding joint: This type rotational movement. It is present in the of joint allows gliding neck region of the backbone. It helps our movement of bones. It head to rotate at the neck. is found in the bones of the wrist, ankle and the backbone. Pivot joint Gliding joint The Skeletal System 11
Functions of the skeletal system The skeletal system has the following functions. 1) Gives shape and support: It gives shape and support to our body. For example, the 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! 2) P rotection of internal organs: It protects the organs inside our body. For example, the rib cage protects the lungs and the heart. The skull protects the brain and the facial organs, while the backbone protects the spinal cord. Skull protects the brain 3) M ovement of body parts: It helps in the movement and facial organs of different parts of the body. Bones and joints cannot move on their own. The muscles attached to them help in their movements. Muscles are flexible. They can stretch and shrink like a spring or rubber band. They pull bones and help joints to twist and turn. 4) S torage of minerals: Bones store minerals like calcium and phosphorus inside them. These minerals make the bones strong enough to support our body. 5) Blood production: The bone marrow Bone marrow present inside the bones produces an Bone marrow inside a bone important component of the blood called red blood cells. Ways to keep our bones and muscles healthy We discussed how important our bones and muscles are. We should take proper care of our bones and muscles so that we can be healthy and strong. Here are some ways to keep our bones and muscles strong. Healthy food: For the health of our bones and muscles, it is important to eat food items rich in proteins, vitamins and minerals. Proteins help in the growth of our body. They help in building muscles, too. Food items such as pulses, milk and milk products are rich in proteins. Vitamin D and minerals like calcium make our bones strong. Vitamin D helps our body to absorb calcium from the food we eat. Food items which contain these nutrients are leafy vegetables, pulses and milk products. Food items like cheese, egg yolk and some fatty fish are rich in vitamin D. 12
Leafy vegetables Pulses Milk products Vitamin C helps to repair the cartilages ? Name any two food items that in bones. Fruits like lemon and oranges keep our bones healthy. are rich in vitamin C. Good posture: The way we hold our body when we sit or stand is called posture. Sitting or standing with a bend is harmful to the bones and muscles. So, we should always sit upright to keep our bones strong. Good and bad postures Exercise and play: Playing and exercising regularly keep our bones and muscles strong and healthy. Activities like walking, running and playing outdoor games like football and tennis are good for the health of our bones and muscles. Exercises such as stretching and simple yoga also help in keeping us fit and fine. Connect the Dots Social Studies Fun Apes and humans have a similar skeletal system. This shows that apes and humans have common ancestors. The Skeletal System 13
Maths Fun Humans have 27 bones in one hand. Calculate the total number of bones in the hands of five people. Bones in one hand = 27 Bones in two hands = 27 x 2 = ____________ Bones in hands of five people = __________ x 5 = ____________ A Note to Parent Talk to your child about the food that keeps our bones healthy. Encourage him or her to have more calcium-rich food items. Some examples are given below: • milk and milk products • green vegetables such as broccoli, cabbage • soya beans and soya drinks • nuts • bread • fish such as sardines 14
3Lesson Healthy Food I Will Learn About • the components and importance of a balanced diet. • the harmful effects of junk food. • ways to make our diet healthier. • diseases related to food habits and lifestyle and how we can prevent them. • deficiency diseases and ways to prevent them. • adulteration of food. I Think Radha was feeling tired and low on energy. She had difficulty breathing. Her mother took her to a doctor. The doctor advised her to eat lots of spinach and beetroot. Do you know why? The components and importance of a balanced diet The food we eat provides our body with essential nutrients to keep us healthy and disease free. We learnt in previous classes that there are five primary components of food: • Carbohydrates • Fats • Proteins • Vitamins • Minerals In addition, other food components are water and fibres. All these components are required in specific amounts to keep our body healthy. A balanced diet contains all of these components in correct amounts for the proper and 15
healthy functioning of the human body. Fats Proteins Vitamins Minerals Carbohydrates A balanced diet Why do we need a balanced diet? 1) A balanced diet provides the body with energy. 2) It allows the body to grow and develop properly and perform all functions. 3) It gives our body the power to fight against disease-causing agents. 4) A balanced diet prevents unnecessary weight gain. 5) It helps in maintaining a healthy and active lifestyle. 6) It helps in the development and proper A balanced diet keeps functioning of the brain. A balanced diet help our body and mind fit us to think, remember and focus in a better and disease-free. way. The harmful effects of junk food Junk food is often very tasty but not healthy. It contains lots of sugar, salt, and fats but is very low on nutrients. Common junk foods are chocolates, pizzas, burgers, French fries, fizzy drinks, chips and so on. Consuming a lot of junk food can cause nutrient deficiency, poor digestion, fatigue and poor concentration. It also results in health problems like obesity. Obesity is a health problem where a person is extremely overweight. It also causes diabetes (high levels of sugar in the blood), high blood pressure, anaemia and heart problems. Therefore, we should avoid junk food as much as possible. Junk food We should also try to have a healthy diet on a daily basis. 16
Now, let us learn a few ways to make ? Give one harmful effect of junk food. our diet healthier. Ways to make our diet healthier We can improve our diet and eating habits in many ways: 1) Eating fresh and natural food: We can eat seasonal fruits and vegetables. We can also eat some fruits and vegetables like apples, grapes, carrots and radishes without peeling. We can include more salads in our meals. We can also consume whole grains. They are rich in fibre and nutrients. 2) Sprouting and fermentation: Sprouts Fermented food items Sprouting pulses increases their nutrient value, and are also easy to digest. We can include sprouts in at least one meal. Fermentation allows food to be easily digested. Examples of fermented food are Idli, vada, dosa and dhokla. 3) Using healthier cooking methods: We should use less sugar and salt in our food and avoid adding extra salt to cooked food. We should eat more of steam cooked food; avoid deep frying and reusing oil. Also, we can mix different food items in a dish to make it more nutritious. Diseases related to food habits and lifestyle and how we can prevent them When we do not maintain a healthy lifestyle, we can have a lot of health problems. Eating a lot of junk food and doing little or no outdoor activity can lead to a lot of lifestyle related diseases. Let us look at a few of them. Disease Causes Symptoms Obesity consumption of too much extreme weight gain, junk food and little or no fatigue and poor (excessive physical and outdoor concentration weight gain) activity Healthy Food 17
Disease Causes Symptoms Hypertension undue stress, lack of dizziness, nausea, breathlessness, exercise, eating a lot of fatigue (High blood salt in food pressure) Diabetes obesity, stress and no increased thirst, extreme hunger, exercise frequent urination, weight loss, (High blood weakness and skin, lung and urinary sugar levels) infections We can often prevent these diseases by following a proper lifestyle. A few ways to do this are: 1) Maintain a proper diet: • Drink enough water every day. Bad eating habits • Avoid junk food as far as possible. combined with an • Include fresh fruits, salads and yogurt in your diet. unhealthy lifestyle may • Make sure your diet has all nutrients. lead to several diseases. 2) Maintain healthy habits: These are called lifestyle diseases. • Get enough sleep every day. • Wake up early and go to bed early. • Exercise or practice yoga for at least 30 minutes every day. • Practice dancing or play an outdoor sport like badminton. • Travel using a bicycle or walk short distances. • Use stairs instead of elevators and escalators. ? Name one disease caused due to unhealthy lifestyle. Deficiency diseases and ways to prevent them When we eat an improper diet or do not exercise, our body may not get enough nutrients. For example, not eating fruits leads to lack of vitamin C. Less exposure to sunlight causes vitamin D deficiency. Deficiency is a serious lack of a specific nutrient. Prolonged deficiency causes deficiency diseases. 18
The table below lists a few common deficiency diseases: Disease Kwashiorkor Marasmus children under the age of children with protein and Whom does it affect five who do not get enough carbohydrate deficiency protein in their daily diet weight loss, weak bones, loose and dry skin, weak legs, reduced growth, paleness, excessive loose motions swelling in the abdomen and other body parts, discolouration of hair, scaly and dry skin, frequent infections Symptoms Causes protein deficiency protein and carbohydrate Prevention deficiency eating protein-rich food items eating a diet rich in cereals, like meat, eggs and milk milk and eggs Disease Anaemia Night Blindness Whom does it affect adults and children adults and children Symptoms headaches, dark patches poor vision, difficulty in seeing under the eyes, fatigue and in dim light and at night, dry paleness and itchy eyes Causes iron deficiency vitamin A deficiency Prevention eating an iron-rich diet such eating food items rich in as dates, raisins, jaggery, vitamin A such as carrots, apples and green leafy papaya, mangoes, egg yolk vegetables and green leafy vegetables Healthy Food 19
Disease Goitre Beriberi Whom does it affect adults and children adults, pregnant women and children swelling of the front portion of fatigue, swollen legs, the neck breathlessness and poor vision coughing and difficulty in breathing Symptoms Causes iodine deficiency vitamin B1 deficiency Prevention using iodised salt while eating food items rich in cooking, eating seafood rich vitamin B such as, soya beans, in iodine legumes, eggs, whole grains and meat 20
Disease Scurvy Rickets Whom does it affect adults, children and people mostly children and sometimes at sea adults weak bones, bow legs, knock swollen and bleeding knees and delayed growth gums, joint pain, difficulty in breathing and slow healing of wounds Symptoms Causes vitamin C deficiency vitamin D deficiency Prevention • spending some time in the sunlight early morning. • eating oranges, lemons • sunlight helps to form and guava vitamin D in the body from • eating vegetables such as the food consumed. cabbage and spinach • eating food items such as eggs and saltwater fish and drinking milk ? Name one disease caused due to the lack of vitamin C in the diet. Be Amaze A d James Lind, a Scottish doctor from Royal Navy discovered that scurvy is caused due to the lack of vitamin C. He also found out that eating citrus fruits can help one recover from scurvy. James Lind Healthy Food 21
Sometimes even after eating a balanced diet, we get sick due to the presence of certain unwanted materials in the food. How do these materials get added to our food? Adulteration of food Have you seen your mother pick out certain things from the rice and then wash it in water before cooking? Can you tell why? She removes the unwanted materials like husk and impurities like tiny stones from the rice and makes it safe for us to eat it. Adulteration is the addition of unwanted or poorer quality materials to food items. This helps sellers to increase the quantity of the food or improve the appearance of food items. The materials added in the food are called adulterants. Adulterants can be in the solid, liquid or powder form. Most of these adulterants are available at a very low cost compared to the cost of the food items. By adulterating food items, sellers can make more profit. Let us examine a few of them. Common Adulterants Food items they are Reason mixed in Water Milk and juices To increase the quantity of the milk and juices Marble and chalk powder Rice, rice powder, sugar To make the food heavier and salt and whiter Metanil yellow pigment Turmeric powder To increase the weight of turmeric and improve its colour Brick powder Chilli powder To increase the weight of the chilli powder Stone chips Cereals and pulses To increase the weight of the cereals and pulses Pumpkin pulp Tomato juice To increase the quantity of the tomato juice These unwanted materials often cause many health problems. Adulteration is punishable under the Indian law. 22
Connect the Dots English Fun Find the names of diseases from the jumbled words given below. 1) YUSRCV: _________________________________________________________________ 2) WHOKARIORKS: __________________________________________________________ Maths Fun A seller mixes 1 kg of chalk powder to 5 kg of sugar. What is the fraction of the adulteration in this? Total amount of sugar after mixing chalk powder = amount of chalk powder + amount of sugar = 1 kg + 5 kg = _________ kg Therefore, fraction of adulteration = total amount of chalk powder powder amount of sugar after mixing chalk = A Note to Parent Print a picture of a rainbow and place it on your refrigerator. Encourage your child to eat a different coloured fruit and vegetable every day using the colours of the rainbow. For example, tomatoes and watermelon are red, berries and beetroot are violet, and mangoes and carrots are orange. Healthy Food 23
4Lesson Pollination I Will Learn About • parts of a flower. • bisexual and monosexual flowers. • the need of pollination for plants. • the process of pollination. • self and cross-pollination. I Think Neha often sees butterflies and honeybees in her surrounding. They sit on the flowers of the plants in a garden near her house. She wonders why they do that. Do you know why? You must have seen many flowering plants. They have colourful and attractive flowers. What parts does a flower have? Parts of a flower Can you recollect the names of the parts of a flower that you studied about in previous classes? You learnt about the sepals and the petals of a flower. Now, let us learn about the parts of a flower in detail. Try this! Take a hibiscus flower. Observe its parts carefully. What do you see? It has many whorls. 24
Now, observe each whorls of the flower. We can see that the shape, size, colour and arrangement of the whorls are different. The green coloured outermost whorl is called calyx. It consists of green, leaf like structures called sepals. Sepals protect the flower in its bud stage. After the calyx, towards the inside we can see a whorl of red coloured petals. This whorl is called the corolla. Generally, the corolla is the most attractive part of a flower. The corolla of some flowers is fragrant (have a sweet smell) and attracts insects and birds towards it. Inside the corolla is a tube-like structure with many hairy outgrowths towards the upper end. These hair-like structures with a yellow box at their ends are the stamens. All the stamens together form the androecium, the male part of the flower. The stalk of a stamen is called the filament. The box like part at the tip of the filament is the anther. Now, gently tap on anther. You can see a yellow powdery material coming out of it. These are the pollen grains. They contain the male gametes. Now, cut the flower into two halves with the help of your teacher. Be careful that the inner parts of the flower does not get Stigma damaged. Carefully observe one half of the flower. What do you see? Style Anther Stamen At the centre of the flower, towards the Filament bottom, we can find a sac-like part. This is the ovary. Inside the ovary we can see small grain-like structures, the ovules. Each ovule contains a female gamete. A thin tube arises from the upper end of the ovary, runs through the tube of stamens and branches out at the tip. This tube is Petal the style. The tip of the style is called the stigma. Now, touch this part softly. How do Ovary Sepal you find it? It is sticky. Ovule The ovules, ovary, style and the stigma together form the pistil or carpel, the female part of the flower. All the pistils or Parts of a hibiscus flower carpels of the flower together form the female whorl of the flower, the gynoecium. The hibiscus flower has five pistils fused together. Pollination 25
We have learnt about the different whorls of The different whorls of a flower are: calyx, corolla, androecium a hibiscus flower. Do all kinds of flowers have and gynoecium. all these parts in them? Some flowers do not Name the four whorls of a flower. have all these parts. Based on the presence or absence of the male and female whorls, flowers are of two types: bisexual and ? monosexual. Let us learn about them in detail. Bisexual and monosexual flowers In most of the plants, the flowers have both male and female parts (the stamen and the pistil). Such flowers are called bisexual flowers. They Bisexual flowers (complete flowers) are also known as complete flowers. For example, hibiscus, rose and jasmine. In some plants, the flowers Rose Jasmine contain either the male part (stamen) or the female part (pistil). Such flowers are called monosexual flowers. They are also known as incomplete flowers. For example, flowers of the pumpkin and papaya. Monosexual flowers (incomplete flowers) Papaya – Papaya – Pumpkin – Pumpkin – male flower female flower male flower female flower The need of pollination for plants We learnt in previous classes that the main function of flowers is to form fruits and seeds. To form seeds, the male and female cells (gametes) of the flowers need to come in contact with each other. As the first step for this, the pollen from the anthers should reach the stigma of the flower. 26
This process of transferring ? Name the process of transferring pollen pollen grains from the grains from the anther to the stigma. anthers of a flower to the stigma of the same or another flower is called pollination. Let us see how pollination takes place in flowers. The process of pollination We have seen that most of the flowers have colourful and attractive petals. Some of them have fragrances too. Most of them produce a sweet liquid called nectar. All these serve the purpose of attracting insects or birds. You might have seen bees, butterflies and birds sitting on flowers. Pollination They sit on flowers to feed on pollen and nectar. When they touch or move around the flower, the pollen grains from the anthers stick to parts of their body. When they sit on another flower, the pollen grains that were stuck to their body may fall off there or stick to the stigma of that flower. Other than insects and birds, bats, water and wind may also transfer pollen grains from one flower to another. They are called pollinators. Be Amaze A d Not all flowers produce pleasant smells to attract pollinators. Some of them give out a foul smell. For example, the flowers of the elephant yam give out the smell of rotting flesh! Elephant yam flower Pollen transfer to stigma may happen within the same flower or between flowers. Based on this, pollination is of two different types: self-pollination and cross-pollination. Let us read about them in detail. Pollination 27
Self and cross-pollination If the pollen grains are transferred to the same flower or to another flower of the same plant, it is called self-pollination. If the pollen grains are transferred to the flower of another plant, it is called cross-pollination. Self-pollination Cross-pollination Self-pollination Self and cross-pollination Connect the Dots English Fun The word ‘gynoecium’ originated from two Greek words – ‘gunaik’ meaning woman and ‘oikos’ meaning house. Find out the origin of the word ‘androecium’. ________________________________________________________________________________ ________________________________________________________________________________ 28
Maths Fun In a village, there were 100 flowering plants. Out of those 100 plants, 25 were pollinated by the wind, 15 were pollinated by bats, 40 were pollinated by insects, and 20 were pollinated by water. Represent this data using tally marks. Data Tally marks The number of flowering plants pollinated by the wind = 25 The number of flowering plants pollinated by bats = 15 The number of flowering plants pollinated by insects = 40 The number of flowering plants pollinated by water = 20 A Note to Parent Take your child to a garden in your neighbourhood. Help him/her identify the different whorls of some flowers. Let him/her identify flowers that have a pleasant smell and would attract pollinators. Pollination 29
A Inside the Lab Make sure you do these activities only with the help of a teacher or an adult. Activity A1: Hear Your Heartbeats Have you ever been sick and visited a doctor? Have you seen the doctor using a stethoscope to listen to the sounds that comes from the inside of your body? Usually, we can’t hear these sounds very well. However, it is audible using a stethoscope. With the help of the stethoscope, the doctor can listen your heartbeat and the sound of the air going in and out of your lungs. Heartbeat is the sound your heart makes while pumping blood. Let us make a stethoscope to hear our heartbeat. You will need: two plastic funnels, a long clear plastic tube that can either fit over the small end of the funnel, one balloon, electrical tape and a pair of scissors. You need to: 1) T ake a balloon. Stretch the balloon by blowing it up and then, letting the air out. 2) Cut off the neck of the balloon. 3) T ightly pull the remaining part of the balloon flat over the open end of any funnel. 4) Secure it with an electrical tape. 5) T ake the plastic tube and put the small end of the funnel onto one end of the tube. 6) P ush the funnel as far as you can to ensure it is properly fit. 7) Put the other funnel onto the free end of the tube. 8) Tape the tubing to the funnels to secure the ends. 30
9) Place the balloon end over your chest and listen through the other end. You can use it to hear the heartbeat of others too. Activity A2: Germ Charades You will need: chart paper, marker and a pair of scissors. You need to: 1) Divide the class into two teams – team A and team B. 2) Let both the teams make disease prevention cards. 3) Cut out small cards from the chart paper. 4) Write various methods of prevention to keep us away from diseases. 5) One learner from team B picks a card from team A. The learner then enacts the method of prevention mentioned in the card without speaking any words. Two minutes can be allotted to each learner to enact the given preventive method. 6 ) gReumesas itnhinegmmeethmobdeorsf po freteveanmtioBna. re required to 7) Reverse the roles. Now, a learner from team A will pick a card from team B and enact the method of prevention written on it. Inside the Lab – A 31
5Lesson Reproduction in Plants I Will Learn About • sexual reproduction in plants. • dispersal of seeds. • plant reproduction through the stem, roots and leaves. I Think Aman likes to eat lots of fruits, but he always wonders how fruits grow on plants. Do you know the answer to this? We learnt in previous classes that seeds of plants germinate to form baby plants. Plants can reproduce (recreate) through seeds. All living things reproduce. Otherwise, they will die out and disappear from the Earth. Plant reproduction through seeds involves the fusion of male and female gametes. So, it is called sexual reproduction. In the previous lesson, we saw that pollination is the first step towards the formation of seeds. What happens after the pollination? How does pollination help in sexual reproduction? Let us find out. Sexual reproduction in plants During pollination, pollen grains are transferred from the anthers to the sticky stigma of the flower. 32
Through the style, the pollen grain forms a Pollen grain small tube called the pollen tube. The pollen tube then reaches the ovary and fuses with Pollen tube the ovules. The pollen tube contains the male cell or male gamete, and the ovules contain the female reproductive cells or the female Ovary gametes. The male and female gametes Ovule meet and fuse together to form a zygote. This process in which the male and female gametes fuse together to form a zygote is Pollen grain growing a pollen tube called fertilisation. towards the ovules in the ovary The zygote then turns into an embryo, which then turns into a baby plant. Fertilised ovules slowly develop into seeds. At the same time, the walls of the ovary increase in size and change into a fruit. Dispersal of seeds When fruits are ripe, they fall off the plant. After a few days, the fruit may decay or dry up, and the seeds get exposed. Have you seen ripe mangoes falling from trees? What will happen if all the seeds fall below the plant and germinate there? They will not have enough space to grow. The nutrients in the soil will not be enough for all of them to grow. So, the seeds of plants need to be scattered in different places. This scattering of seeds from the plants in different places is known as the dispersal of seeds. How does dispersal take place? 1) Wind: Some seeds get flown away by the wind. For example, the Dispersal of seeds seeds of the dandelion plant. Have you seen any fluffy seeds by wind gliding in the air? 2) W ater: Seeds of the lotus plant or coconut tree, which grow in or around water bodies, are dispersed by water. These types of seeds float on water. 3) Animals: Seeds of some plants are sticky. They get attached to Dispersal of seeds the body of animals. When these animals move from one place by water to another, these seeds attached to their body may fall off at different places. For example, grass seeds. Dispersal of seeds by birds Some birds eat fruits. Sometimes, the seeds fall off accidentally from their beaks. Some birds may spit the seed after eating the fruit. And sometimes, seeds reach the soil through the bird droppings. Animals like bats are also involved in the dispersal of seeds. Reproduction in Plants 33
For example, banyan, guava and so on. Human beings also help in the dispersal of seeds. For example, seeds get stuck to the clothes and shoes of farmers and may fall off at different places. ? Name any one seed dispersed by animals. 4) E xplosion: Seeds of some plants are dispersed by fruit Dispersal of seeds explosion. For example, ladyfinger and mustard. by fruit explosion After dispersal, seeds reach the soil. In the soil, they The spreading of seeds germinate and turn into new plants. from plants to different places is known as the Do all seeds grow into new plants? Seeds need moisture, dispersal of seeds. air and the right amount of warmth to germinate and grow. Until they have these conditions, seeds do not sprout. Once a seed gets the right conditions, it turns into a tiny baby plant and then grows into a new plant. Plant reproduction through the stem, roots and leaves Reproduction in plants may not always involve fusion of male and female gametes. Some plants reproduce through their stems, leaves or roots. This type of reproduction is called vegetative reproduction. Let us discuss a few examples of vegetative reproduction in plants. Leaf 1) Plants that reproduce through leaves: bud Some plants like bryophyllum have bud- like structures along the margins of their leaves. These buds develop into new plants when they fall into moist soil. 2) Plants that reproduce through stems: Leaf buds grow into new plants in Stems such as the potato, onion, ginger, bryophyllum sugarcane and so on grow into new plants. You might have seen small, greenish, bud-like structures on potato; they are called the ‘eyes’ of the potato. These eye buds on the potato grow into new plants. In ginger, the stem with a bud on it grows into a new plant. The stems of the plants such as rose, hibiscus Buds on potato Bud on ginger and jasmine also grow into new plants. 34
Reproduction in hibiscus plants through stems The stem is cut The cut portion of the stem is planted in a pot/in the soil and it grows into a new plant In onion, a new plant develops from a special structure called a bulb, which is a modified stem. 3) Plants that reproduce through roots: Roots of plants like carrot and radish develop shoots (stems), which later develop into new plants. We can observe reproduction in carrot Radish roots develop Onion plant through a simple activity. shoots that develop developing from into new plants a bulb Try This! Take a carrot and cut off its top portion. Place the cut portion in a dish with the cut end facing downwards. Pour water into the dish so that the cut portion of the carrot remains dipped in the water. Keep the dish in a place where it can get enough sunlight. Daily observe the cut portion of the carrot in the dish. After a few days, a new plant will grow from it. Be Amaze Reproduction in carrot through root A d Plants such as mosses and ferns do not have flowers and seeds. They bear spores. These are special structures that are used for reproduction instead of seeds. Fern leaf with spores Reproduction in Plants 35
Connect the Dots English Fun Make verbs from the following nouns: 1) dispersal: _____________________________________________________________ 2) reproduction: _________________________________________________________ 3) pollination: ____________________________________________________________ 4) germination: __________________________________________________________ Maths Fun Mode of dispersal Number of plants Air 180 Here is some data 120 about the seed Water 200 dispersal of some Animals plants. Draw a bar graph to represent the data. A Note to Parent Help your child to identify male and female reproductive parts of the flowers seen in your surroundings. 36
6Lesson Solids, Liquids and Gases I Will Learn About • properties of solids. • properties of liquids. • properties of gases. • the composition of different gases in the air. • the need for ventilators and windows in buildings. • air in motion – wind, breeze and storm. I Think Can you recollect the different forms of matter that we studied before? Can you name some materials that are found in these states? We learnt about the three main states of matter such as solids, liquids and gases in previous classes. Now, let us study their properties in detail. Everything around us is made up of matter. Matter takes up space. It is made of very small particles. These particles are arranged ? Name the three states inside the matter in different ways. This is why of matter. matter exists in different forms such as solids, liquids or gases. Let us now learn about the properties of solids, liquids and gases. Properties of solids We know that the particles in the solid state are very close to each other and tightly packed. They cannot move around as there is no space between them. Because of this, solids have a fixed shape. 37
Wood, stone and paper are a few examples of solids. Now, let us learn about a few other properties of solids. Try this! Take 1 litre measuring jars of two different shapes (One cylindrical and one conical). Add common salt to fill the cylindrical jar up to the 500 ml mark. Now, transfer the salt from the cylindrical jar to the conical jar. What do you see? The salt level is exactly at the 500 ml mark in the conical jar as well. What do we understand from this activity? A specific quantity of salt needs a specific amount of space to occupy. The amount of space that an object or a substance occupies is called its volume. Thus, solids have a specific volume. Try this! 1) Take a rubber band and stretch it. What do you see? It changes its shape. Now, remove the applied force. What happens? 2) T ake a sponge and squeeze it. It changes its shape. What happens when you leave it? 3) T ake some clay in your hands and give it some shape by applying force. When you remove the force, does the clay return to its original shape? From this, we can conclude that some solids can change their shapes when force is applied to them. For example, sponge, clay, rubber and so on. Among these, sponge and rubber bands return to their original shape once the force is removed. However, clay does not automatically go back to its original shape. Try this! Take some sugar and observe it using a magnifying lens. What do you see? You can see that the sugar granules are of a specific shape. They look like crystals. Now, observe some copper sulphate under the magnifying lens. You can see that copper sulphate is also in the crystal form. Sugar crystals Copper sulphate crystals 38
Now, take some gel (hair gel/shower gel/toothpaste gel). Observe it. Can you see any crystals in it? No. Based on this activity we can conclude that some solids are present in crystal form while others are not. Why are they different? Solids differ in the arrangement of particles within them. Crystalline solids have particles arranged in a repetitive pattern. For example, sugar, salt, copper sulphate and sand. Other solids do not have such a pattern. For example, gels, rubber and glass. Thus, we can summarise the properties of solids as follows: a) S olids do not flow. b) They have a definite shape. c) S ome solids change their shape when force is applied. d) S ome solids are in the form of crystals. e) The particles of solids are tightly packed. f) T hey have a definite volume. Particle arrangement in solids Properties of liquids In liquids, the particles are not packed very closely. They have some space between them. So, they can move around. Water, milk and kerosene are a few examples of liquids. Try this! You will need: glass containers of various shapes (bowl, glass, beaker, flask and so on), water and different water colours. You need to: 1) Pour some water into each of the containers. 2) A dd some colour to each of the containers Liquids take the shape of the and mix. (Choose a different colour for each container container.) For example, ink, turmeric and so on. 3) Observe how water is held in each container. Note your observations. We observe that liquids do not have a definite shape. They take the shape of the container that they are poured into. Solids, Liquids and Gases 39
Try this! Take two 1 litre measuring jars of different shapes (one cylindrical and one conical). Take some water and add some food colour or ink to it. Pour the coloured water into the cylindrical jar upto the 500 ml mark. Now, pour the water from the cylindrical jar into the conical jar. What do you see? The water level is exactly at the 500 ml mark. What do we understand Measuring jars from this activity? A specific quantity of water needs a specific amount of space to occupy. This shows that water has volume. The properties of liquids can be summarised as: a) T he particles of liquids are loosely packed. So, they can flow from a higher level to a lower level. b) Liquids do not have a definite shape. They take the shape of Arrangement of the containers into which they are poured. particles in liquids c) They have a definite volume. Properties of gases In gases, the particles are spaced far away from each other. So they can move easily in all directions. Oxygen, carbon dioxide and nitrogen present in air are a few examples of gases. Try this! 1) T ake a wide-mouthed glass vessel. 2) Cover the glass vessel with a cardboard piece with a hole in the centre. 3) L ight an incense stick and insert it into the vessel through the hole in the cardboard. 4) L et the smoke fill the glass vessel. 5) R emove the incense stick and the cardboard and immediately cover the mouth of the glass vessel with an inverted glass jar. What do you see? The smoke also fills up the glass jar. We can, therefore, conclude that gases do not have a definite shape and volume. 40
Thus, the properties of gases can be summarised as: a) G ases do not have a definite shape and volume. They occupy all the space in the container that they are kept in. b) P articles in gases are very loosely packed and have lots of space in between them. So, they can move easily in all directions. Be Amaze Arrangement of particles in gases A d Do you know that there is a layer of a gas called ozone in our atmosphere? This layer protects us from harmful ultra violet (UV) rays of the Sun. The composition of different gases in the air Ozone layer Nitrogen The air around us is a mixture of gases. The circle in the diagram represents all the air around us. If we divide the circle into ten equal parts, then the oxygen in the air will be approximately equal to two parts. Nitrogen will take almost eight parts and the remaining small part is composed of gases like carbon dioxide, argon, water vapour and so on. In air, oxygen is available in Carbon dioxide, Oxygen approximately 2 out of 10 parts, argon, water vapour nitrogen occupies almost 8 out of 10 parts, and the remaining part and other gases consists of carbon dioxide, argon, water vapour and other gases. Composition of air Let us conduct an activity to find out the presence of water vapour in air. Solids, Liquids and Gases 41
Try this! Take a glass. Put a few ice cubes in it and keep it on a table. Wait for 5 minutes and then, observe the glass. What do you see? There are small droplets of water on the outer side of the glass. Why did this happen? The outer side of the glass cooled down due to the ice cubes inside it. Because of this, when the water vapour present in air comes into contact with the cool glass surface, it changes its form to water. Hence, we can conclude that air contains water vapour. The need for ventilators and windows in buildings In previous classes we have learnt that warm air is lighter than cold air, and it moves upwards. The cooler air, being heavier, takes the place of the warmer air. This causes air movement. The air in the atmosphere gets heated due to the Sun’s heat. In the same way, the air in our houses also gets heated due to many reasons such as breathing out warm air, cooking activities in the house and so on. Being lighter, this warm air goes up. Ventilators near the Ventilators An exhaust fan in a roof help to drive away this kitchen warm air. Foul smells and strong smells of cooking also escape through the ventilators and exhaust fans. Windows bring in fresh, cool air into our houses. So, we should have windows and ventilators in our houses. We should always have cross-ventilation in our houses to keep the fresh air circulating. This is brought about by having windows on opposite facing walls of the room. If we don’t have sufficient airflow, moisture and germs can build up in our houses. This can affect our health. Moisture may also damage our furniture. Hence, to keep our houses healthy, fresh, airy and dry, we should have ventilators, windows and exhaust fans in our houses. ? Why do we need Cross-ventilation ventilators in our houses? 42
In addition to these, we use appliances like ceiling fans, table fans, air conditioners and coolers to keep ourselves cool during the hot summer months. They help by bringing down the temperature of a room. In rainy and winter seasons, we reduce the use of these appliances as the weather is cold. We use room heaters during winters. Air in motion – wind, breeze and storm We now know that heating causes movement of air. What is wind? ?We call the moving air wind. A gentle wind is called a breeze. Breezes are of different types. Let us learn about some of them. • Sea breeze: During the day, the land heats up faster than the sea due to the Sun’s heat. The air on the land also gets heated up. Being warmer, it rises up. The cooler and heavier air on the sea rushes into the land to take up the space of the risen warm air. The cooler air that moves from the sea to the land during the daytime is called the sea breeze. • Land breeze: At night, the land cools down faster than the sea. Now the sea is warmer and so is the air over the sea. This air then rises up as it is warmer. The air on the land rushes to the sea, to take up the space of the risen warm air. The cooler air that moves from the land to the sea at night is called the land breeze. Sea breeze Land breeze • Monsoon breeze: Near the equator, during summer, the land warms up faster than the sea due to the direct rays of the Sun. The air above the land also gets heated up. Being warmer, the air on the land rises upwards. The winds from the seas have moisture in them. This moisture- laden air moves up towards the land to take the place of the risen air. This air moving from the sea towards the land is Monsoon breeze called the monsoon breeze or monsoon wind. In India, we get rainfall due to these monsoon winds. Solids, Liquids and Gases 43
When the wind is strong, and it blows very fast, it is A gentle wind is called called a storm. a breeze. The main types of breezes are: sea breeze, land • When storms bring in heavy rain, thunder and breeze and monsoon breeze. lightning, they are called thunderstorms. Monsoon breeze gives us rain. • Some storms carry dust with them. They are called dust storms. • The storms that carry sand are called sandstorms. • Some storms bring snowfall. They are called snow storms. ? Name any one type of storm. Connect the Dots Maths Fun Out of the 13 substances required to carry out an experiment, 8 are in the solid form, and 5 are in the liquid form. Represent this data using fractions. Substances required to carry out the experiment = 13 Substances in the solid form = . Substances in the liquid form = . Thus, the fraction of substances in the solid form = 13 and the fraction of substances in the liquid form = 13 . 44
English Fun Underline the adverbs in the following sentences. a) The particles in solids are closely packed. b) Liquids flow easily when spilt. c) Particles in gases move around freely. A Note to Parent Talk to your child about the importance of ventilation in the house. Talk about various devices that provide ventilation. For example, exhaust fans. Also, discuss various devices that keep the air cool. For example, coolers. Solids, Liquids and Gases 45
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