Reflection
Science
Acknowledgements
Academic Authors: Latika Uppal, Cherry Chadha, Akanksha Singh, Kashika Parnami, Chandani Goyal, Anuj Gupta, Simran Singh
Creative Directors: Bhavna Tripathi, Mangal Singh Rana, Satish
Book Production: Sanjay Kumar Goel, Vishesh Agarwal
Project Lead: Sneha Sharma
VP, Learning: Abhishek Bhatnagar
All products and brand names used in this book are trademarks, registered trademarks or trade names of their respective owners.
© Uolo EdTech Private Limited
First impression 2025
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Book Title: Reflection Science 5
ISBN: 978-81-979832-7-6
Published by Uolo EdTech Private Limited
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Preface
Welcome to the exciting world of science through Reflection, a textbook that has been thoughtfully designed to ignite curiosity, and nurture a love for evidence-based thinking in young minds.
In today’s rapidly evolving world, a solid foundation in science from an early age is more crucial than ever. Science education lays the groundwork for critical thinking, problem-solving, and the ability to make informed choices. These skills are not just academic: they are essential life skills that empower young minds to understand and interact with the world around them in a rational and meaningful way. At UOLO, we believe that every child deserves to learn these skills with the best resources available.
In this pursuit, Reflection is uniquely crafted to provide a comprehensive and contemporary learning experience, meticulously aligned with the recommendations of the National Education Policy (NEP) 2020 and the National Curriculum Framework (NCF) 2023. The book incorporates the curricular goals and competencies outlined in the NCF 2023, ensuring that every chapter, exercise, and feature reflects these foundational principles.
This textbook transcends traditional teaching methods by adopting a competency-based approach, recommended by both NEP 2020 and NCF 2023, that emphasises not just conceptual understanding and critical thinking, but also application of scientific concepts, and problem-solving. It is designed to make learning both meaningful and relevant, equipping students with the tools they need to thrive in the 21st century.
Carefully curated content, NEP-specific tags, and a diverse array of elements have been seamlessly integrated throughout the book to nurture essential skills, values, and dispositions outlined in the NEP. Competency-based projects and assessments are strategically placed to help students master key concepts and develop higher-order thinking skills.
The book has the unique feature of being complemented by a graphic novella. Each unit of the book begins with an episode of the gripping sci-fi tale, which not only captivates the students’ interest and promotes reading, but also ingeniously connects with some of the core concepts that will be taught in the respective units.
Each chapter is also enriched with vibrant illustrations, relatable examples, and interactive activities to engage our young learners. Hands-on experiments and inquiry-based learning experiences have been embedded throughout the book to instil a scientific temper among students and make learning an enjoyable journey for them. Moreover, assessments ‘of, as, and for learning,’ as envisioned by the NEP and NCF, have been interwoven throughout the curriculum, providing continuous evaluation and meaningful feedback to students to support their growth and success.
The Reflection product bundle offers a comprehensive science kit which includes a textbook that has relevant and up-to-date content, concept building opportunities, projects, and assessments; a teacher manual offering extensive teaching support; technology-powered features that includes engaging videos and interactive exercises for students; and digital lesson plans and an assessment generator for teachers.
In conclusion, Reflection is designed to fascinate students towards science, both as a subject and as a practical experience in their everyday lives, while also making them well-rounded individuals. We invite educators, parents, and students to embrace Reflection and join us in nurturing the next generation of thinkers, innovators, and problem-solvers. Embark on this exciting journey with us and let Reflection be a valuable resource in your educational adventure.
The Product Philosophy
Welcome to the Reflection journey.
The program is carefully designed to elevate the experience of learning science through an NCF-based, age-appropriate, pedagogically-sound, and engaging content. Teachers will be supported with a manual that offers comprehensive guidance to optimise classroom instruction. Furthermore, various assessment mechanisms have been built in to the program.
Engaging Textbooks
Comic Stories
Teacher Manual
ASSESSMENT
Competency-based Model Assessments
STEAM Projects
Question-paper Generator
DIGITAL
Student and Teacher Apps
Learning Videos
Interactive Tasks & Exercises
Byte-size Lesson Modules
The Reflection program is also augmented by a digital learning platform that offers powerful educational videos and interactive exercises to help children master concepts and skills in a joyful and fear-free manner.
Key NEP Recommendations
The National Education Policy (NEP) 2020, introduced by the Government of India, represents a transformative shift in the country’s education system. It aims to create a more holistic, dynamic and multidisciplinary approach to education. NEP 2020 focuses on fostering conceptual understanding, skills, values, and competencies that align with the demands of the 21st century, while also preserving India’s rich cultural heritage. UOLO is fully committed to actualising the vision of NEP 2020 by meticulously adhering to its outlined recommendations.
1. Focus on conceptual understanding
2. 21st century skills, values, and dispositions
3. Critical thinking and problem solving
4. Application in real life
5. Holistic and integrated learning
6. Experiential learning
7. Enjoyable and engaging
8. Scientific-inquiry and discovery-based approach
9. Technology-based solutions
10. Knowledge of India
Competency-based Education
NEP Pages 12, 17, and 22
Teaching and Learning Pedagogy
NEP Pages 3, 11, 12, and 27
National Pride
NEP Pages 15, 16, and 43
11. Assessment of core concepts and application skills Assessments
NEP Pages 12, 18, and 22
Our Key Features: Aligning with NEP 2020
STEAM Projects
Engaging hands-on projects blending Science, Technology, Engineering, Art, and Maths (STEAM) to inspire young minds
Competency-based Assessments
Test papers designed to evaluate the understanding of core concepts and application of skills
Story-based Approach
Enchanting comic stories that bring learning themes to life, making education a captivating adventure
Explore More
Curated videos to find out more about key concepts
Do and Learn
Multidisciplinary, holistic, and fun-filled activities to internalise the concept better
Investigate and Discover
Hands-on experiments to foster the spirit of scientific inquiry and evidence-based thinking
Translating Words into Action
Error Alert
Concise snippets of information designed to caution against potential misconceptions
HOTS
Intellectually stimulating questions designed to encourage deep, analytical, critical, and evaluative thought processes
Interactive
Digital worksheets on key concepts to supplement textbook exercises
Wonders of Bharat
Fascinating insights into India’s rich culture and heritage, designed to ignite a profound sense of pride and love for the nation
Picture-based Questions
featuring visual stimuli to elevate comprehension, interpretation, and critical thinking
Life Skills
Simple activities and tips to develop a diverse set of essential skills for living well
The NEP Tags
The National Education Policy (NEP) 2020 outlines essential skills, values, dispositions, and learning approaches necessary for students to thrive in the 21st century. This textbook identifies and incorporates these elements throughout its content, activities, and exercises. Referred to as “NEP Tags”, they are defined as follows:
INTEGRATED
Art Integration
Bringing creativity and fun into learning by combining music, drama, and art with other subjects
Sports Integration
Using physical activities, sports, and games to make learning active and engaging
Holistic & Integrated Learning
Cross-curricular and skill linkages to make the learning experience more holistic, joyful and meaningful
SCIENTIFIC TEMPER
Scientific Temper
A mindset rooted in curiosity, critical thinking, problem-solving, and evidence-based reasoning
Teamwork
TEAMWORK
SDG
Embracing the spirit of mutual collaboration and cooperation while working together to solve problems
Sustainable Development Goals
Unwavering commitment to create a green, peaceful, prosperous, and equitable and inclusive world
SEL
Social Emotional Learning
Developing the skills to understand and manage emotions, build positive relationships with others, and make responsible choices
GAMES
Education Standards as per the NCF 2023
The National Curriculum Framework for School Education (NCF), released in 2023, is developed based on the vision of the National Education Policy (NEP) 2020. Its purpose is to enable the implementation of the NEP. The NCF provides guidelines for designing school syllabi and textbooks in India. It aims to improve the quality of education by making it more relevant, engaging, inclusive, and learner-centric. To achieve this, the NCF has articulated precise Learning Standards through well-defined Curricular Goals and Competency statements. These statements serve to harmonise the syllabus, content, pedagogical practices, and assessment culture, ensuring a cohesive and comprehensive educational experience.
Curricular Goals: Curricular Goals are statements that give directions to curriculum development and implementation. They are derived from Aims and are specific to a Stage in education.
Competencies: Competencies are learning achievements that are observable and can be assessed systematically. These Competencies are derived from the Curricular Goals and are expected to be attained by the end of a Stage.
NCF Page 59
Curricular Goals
CG-1
Explores the natural and social environment in their surroundings
CG-2
Understands the interdependence in their environment through observation and experiences
Competencies
C-1.1 Observes and identifies the natural (insects, plants, birds, animals, geographical features, sun and moon, soil) and social (houses, relationships) components in their immediate environment
C-1.2 Describes structures, relationships, and traditions in the family and community
C-1.3 Asks questions and makes predictions about simple patterns (season change, food chain, rituals, celebrations) observed in the immediate environment
C-1.4 Explains the functioning of local institutions (family, school, bank/ post office, market, and panchayat) in different forms (story, drawing, tabulating data, noting discussion), and analyses their role
C-1.5 Creates simple objects (family tree, envelopes, origami) on their own using local materials
C-2.1 Identifies natural and humanmade systems that support their lives (water supply, water cycle, river flow system, life cycle of plants and animals, food, household items, transport, communication, electricity in the home)
C-2.2 Describes the relationship between the natural environment and cultural practices in their immediate environment (nature of work, food, traditions)
C-2.3 Expresses the changes in the lives of their family and community as communicated by elders and through local stories (changes in occupation, food habits, resources, celebrations, communication)
The above is a snapshot of the curricular goals and competencies relationship in EVS for the Preparatory Stage (NCF 2023, pages 340–341). The next section shows the coverage of all these competencies across the chapters.
Mapping with NCF 2023
C-1.1 Observes and identifies the natural (insects, plants, birds, animals, geographical features, sun and moon, soil) and social (houses, relationships) components in their immediate environment
CG-1 Explores the natural and social environment in their surroundings
C-1.2 Describes structures, relationships, and traditions in the family and community
C-1.3 Asks questions and makes predictions about simple patterns (season change, food chain, rituals, celebrations) observed in the immediate environment
C-1.5 Creates simple objects (family tree, envelopes, origami animals) on their own using local materials
C-2.1 Identifies natural and humanmade systems that support their lives (water supply, water cycle, river flow system, life cycle of plants and animals, food, household items, transport, communication, electricity in the home)
CG-2 Understands the interdependence in their environment through observation and experiences
C-2.2 Describes the relationship between the natural environment and cultural practices in their immediate environment (nature of work, food, traditions)
C-3.1 Describes the basic safety needs and protection (health and hygiene, food, water, shelter, precautions, awareness of emergency situations) of humans, birds, and animals
CG-3 Explains how to ensure the safety of self and others in different situations
C-3.2 Discusses how to prepare for emergency situations (pandemic, floods, landslide, unseasonal rains) based on discussions with family and community, or personal experiences
C-3.3 Develops simple labels, slogans, and participates in roleplay on safety and protection in the local environment to be displayed/done in school and locality
C-4.1 Observes and describes diversity among plants, birds, and animals in their immediate environment (shape, sounds, food habits, growth, habitat)
CG-4 Develops sensitivity towards social and natural environment
C-4.2 Observes and describes cultural diversity in their immediate environment (food, clothing, games, different seasons, festivals related to harvest and sowing)
C-4.3 Observes and describes natural resources in their immediate environment, and their use
C-4.5 Identifies needs of plants, birds, and animals, and how they can be supported (water, soil, food, care)
C-6.1 Performs simple investigations related to specific questions independently or in groups
C-6.2 Presents observations and findings through different creative modes (drawing, diagram, poem, play, skit, through oral and written expression)
CG-6 Uses data and information from various sources to investigate questions related to their immediate environment
Chapter at a Glance Walkthrough of Key Elements
5 Plants Around Us
Comic Story: Exciting story built throughout the book, contains hooks to topics in a unit
Chapter Overview: Outline of the key concepts covered in the chapter
Get Set: A short and fun activity to get learners excited about the new topic
You know about different parts of a plant. Solve the crossword puzzle as quickly as you can!
Did You Know? Interesting facts related to the topic
Vocabulary: Meanings of difficult words
Error Alert: Caution against misconceptions
Investigate and Discover: Hands-on experiments to nurture the spirit of curiosity, inquiry and evidence-based thinking
Pause and Answer: Short exercises between the chapter to pause and assess comprehension
NEP Tags: To show alignment with NEP skills and values
Do and Learn: Multidisciplinary, holistic, and fun activities to understand the concept better
Think and Tell / Discuss: Analysis, reflection, and text-to-self connection-based prompts for discussion in class
Remember: Recall of previous knowledge relevant to the topic
Wonders of Bharat: Fascinating insights into India’s rich culture and heritage
Word Splash: Recall of key terms and concepts in the chapter
Explore More: Short videos to find out more about the topic
Points to Remember: Summary of the chapter
Chapter Checkup: Chapter-end practice exercises aligned to different levels of Bloom’s Taxonomy
Picture-based Questions: Special questions featuring visual stimuli to foster comprehension, interpretation, and critical thinking
HOTS: Intellectually stimulating questions designed for higher order thinking and analysis
Life Skills: Simple activities and tips to develop a diverse set of essential skills for living well
1 Food and Health
Chapter Overview
Get Set
Circle the names of five nutrients from the given word search.
MINERALS
PROTEINS VITAMINS
Components of Food
Think about how plants in a garden need different things like sunlight, water and good soil to grow strong and healthy. Our bodies too need a variety of nutrients to grow, perform various functions, and be healthy and strong. We get these nutrients from the healthy foods we eat every day. Different foods provide different nutrients, such as vitamins, minerals, proteins, and carbohydrates. These nutrients are the building blocks of our health. Let’s learn about these essential nutrients, what they do for our bodies, and where we can find them.
Carbohydrates
Carbohydrates are the main source of energy for our body. The different forms of carbohydrates are starches and sugars. Carbohydrates can be found in foods like wheat, rice, potatoes, sugar, honey, corn, etc.
When we eat carbohydrates, our bodies break them down into simple sugars like glucose, which gives us the energy to stay active throughout the day.
Fats
We can imagine fats as the storage units for our bodies. While carbohydrates give us instant energy, fats store energy for later use. They also protect our organs like a cushion, help in the absorption of certain vitamins, and help to keep our bodies warm.
Fats can be found in foods like nuts, seeds, avocados, butter, ghee, cheese and oil. We require fats in very small amounts.
Not all fats are good for us. Unhealthy fats, found in fried and processed foods, cause health problems. Error Alert!
Proteins
Proteins are essential for building, maintaining, and repairing muscles, blood, skin, bones, and other tissues and organs in the body. Because of this important function,
processed food: food changed from its natural state, often to make it last longer or taste better
Carbohydrates
they are known as “body-building nutrients”. Foods rich in protein include meat, eggs, dairy products, fish, beans, soya and pulses.
Growing children and sick people should include more protein-rich food in their meals.
Remember!
When you get cut yourself, your body works hard to heal and repair itself. Proteins play a crucial role in this healing process by helping to repair and build tissues.
Vitamins
Although needed in small amounts, vitamins are crucial for maintaining good health. They are required in very small amounts by our body. You can find vitamins in a variety of foods like fruits, vegetables, dairy products and meats. Vitamins help our body fight against infections. They help to heal wounds and keep our bones and gums strong.
Minerals
Minerals are another group of essential nutrients that help our bodies to stay healthy. Some important minerals include sodium, potassium, calcium, iron, phosphorus and iodine. Calcium is important for strong bones and teeth, while iron helps in carrying oxygen in our blood. Minerals can be found in foods like dairy products, nuts, fruits and green leafy vegetables.
Vitamins and minerals are collectively known as “protective foods” as they are necessary for good health and protecting our body.
Water and Roughage
Did You Know?
Water doesn’t provide any nutrients to our body. However, it’s an important component of food. It’s often referred to as our “body’s lifeblood” because it plays a critical role in almost every bodily function. It aids in digestion, regulates body temperature, maintains skin health, and helps in transporting nutrients to the different parts of the body. We should drink plenty of water every day.
The body of an adult human being consists of about 60% water.
Vitamins and Minerals
Roughage, also known as dietary fibre, is the indigestible part of food. Roughage plays an important role in digestion. It promotes smooth passage of food through the digestive system, preventing constipation. It adds bulk to the food and helps to get rid of the undigested food from the body. Fibre-rich foods like whole grains, fruits and vegetables provide the roughage our bodies need to maintain a healthy digestive system.
Investigate and Discover
Aim: To analyse the nutrient content in a packet of chips.
Materials Needed: a packet of chips (of your choice)
Method:
Step 1: Choose your favourite packet of chips. Make sure the packet includes nutritional information.
Step 2: Look at the nutritional information on the packet. Focus on key nutrients: carbohydrates, fats, proteins, vitamins and minerals.
Step 3: Now look at the amount of salt, sugar, food colours and preservatives.
Findings: A packet of chips contains very high amounts of salt, food colour, oil and preservatives. These items, in such quantities, are not good for health if consumed on a regular basis.
Conclusion: This experiment helps you see the nutrient content in things like a packet of chips. This will help you make healthier choices in terms of what you eat.
Pause and Answer
Write any two food items rich in each of the nutrients listed below.
Carbohydrates
Fats
Proteins
Vitamins
Minerals
indigestible: something that cannot be digested constipation: a condition in which stool becomes hard and is difficult to pass
Maintaining Good Health
Being healthy means your physical and mental well-being. A healthy person eats a balanced diet rich in nutrients, practises good hygiene, maintains good posture, exercises regularly, gets enough rest and sleep, and keeps their surroundings clean. They feel good physically as well as mentally.
Balanced Diet
A balanced diet means eating a variety of foods from all the major food groups to get the nutrients that are required by the body. A balanced diet provides all the essential nutrients for the proper growth and functioning of our body.
Do and Learn
A balanced diet should contain all the nutrients.
Create your own balanced meal! Draw a plate and divide your plate into sections and label each with different food items that make up a balanced meal.
Hygiene
Hygiene is essential for staying healthy and preventing illness. This includes practices that help remove or reduce the number of germs on your body and in your environment. Some hygiene practices that we should follow to stay healthy are listed below.
• Wash your hands with soap and water for at least 20 seconds when they are dirty, before and after meals, and after using the toilet.
• Brush your teeth twice a day. Use a tongue cleaner to clean your tongue.
• Regularly shower to keep your skin clean. Always wear neat and clean clothes after bathing.
• Keep your nails trimmed and clean to prevent the accumulation of dirt and germs, which can cause infections.
• Regular cleaning of kitchens, toilets and bathrooms should be done.
Posture
Hygienic practices
Posture is how we hold our body while standing, sitting, moving or lying down. Good posture means positioning our body in ways that reduce stress on muscles. It helps keep bones and joints strong. Always make sure to keep your back straight while standing, sitting and walking. Correct posture makes your body appear smarter and improves flexibility in joints.
Exercise
Regular exercise is essential for maintaining a healthy body and mind. Walking, cycling, jogging, running, yoga and swimming are some exercises that keep us fit and healthy. Let’s learn about some benefits of regular exercise.
• It makes our bones and muscles strong and healthy.
• It improves the circulation of blood in our body. When we exercise, our heart pumps blood at a faster rate, which leads to more intake of oxygen and better functioning of the body.
• It keeps our body in good shape.
• It makes our body healthier and more flexible.
• It keeps us active and energetic throughout the day.
• It improves our quality of sleep.
Rest and Sleep
We should exercise daily.
Rest and sleep are important for your body to recover and work well. When you sleep, your brain stores memories, helping you to learn better. Your muscles repair themselves, making you feel strong. Sleep also boosts your immune system, so you don’t get sick easily. Besides sleep, taking breaks during the day helps to reduce stress and tiredness, giving your body and mind time to recharge.
accumulation: to collect or gather
Correct posture for sitting
Clean Surroundings
A clean surrounding reduces the risk of infections and other health issues. Let’s learn about how to keep our surroundings clean.
• Regularly clean your room by dusting, sweeping and organising your belongings to reduce the presence of dust.
• Always throw garbage in dustbins.
• All drains in the house should be covered and cleaned properly.
• Avoid letting dirty water accumulate in your surroundings, as it can become a breeding ground for mosquitoes and harmful germs.
Diseases
A disease is a condition in which our body or any part of it is not in a healthy condition. Diseases can be caused by improper diet, or lack of hygiene, rest and exercise. Diseases can be classified into two main types: communicable and non-communicable diseases.
Non-communicable Diseases
These diseases don’t spread from person to person. Some non-communicable diseases are caused due to the lack of nutrients. These are called deficiency diseases. Let’s first learn about some deficiency diseases.
Names of deficiency diseases Caused by deficiency of
Night blindness
Beriberi
Scurvy
Vitamin A
Vitamin B
Vitamin C
Rickets Vitamin D
Anaemia
Goitre Iodine
Apart from deficiency diseases, there are a few other kinds of non-communicable diseases such as:
1. Allergy: Some people are highly sensitive towards certain food items, dust or chemicals. When people are exposed to any of these things, they might sneeze, cough or even become ill. This state or condition is called an allergy.
We should throw garbage properly.
2. Obesity: This occurs due to excess consumption of oily, fried and processed foods or by overeating. Obese people are more prone to heart diseases and diabetes.
3. Diseases like arthritis and diabetes are caused due to malfunctioning of body parts like the joints and the pancreas.
Think and Tell
Reflect on your own eating and exercise habits. What is one healthy change you can make to reduce the risk of diseases?
4. Diseases like cancer can be caused due to environmental pollution, smoking or consumption of alcohol.
5. Some people have heart disease from birth which they inherit from their parents.
Communicable Diseases
These diseases can spread from one person to another or through the environment. These are caused by germs such as bacteria, viruses, fungi and protozoa.
The germs causing communicable diseases can spread in several ways. Let’s learn about them.
Remember!
Not all microbes are bad. Microbes help us in many ways. They are used to make food such as curd, yogurt, cheese and bread. They also help in digestion of food. Scientists use microbes to make medicines like antibiotics.
• Direct Contact: Germs can transfer through physical contact like shaking hands with the infected person. Communicable diseases can also spread by touching or using the belongings, like clothes and utensils, of the infected person. Diseases such as chickenpox, whooping cough, common cold, measles and tuberculosis spread through direct contact.
• Dirty food and water: You might have noticed a lot of mosquitoes, flies and cockroaches sit on the uncovered food and dirty water. These insects carry germs on their bodies and pass them to the uncovered food and water. Consumption of infected food items spreads diseases such as typhoid and cholera.
• Insects or carriers: Some insects, such as mosquitoes, can bite and transmit germs into a person. When the female Anopheles mosquito bites a person already infected with malaria, it sucks in the germs along with the blood of the person. Then, this mosquito bites a healthy person and causes malaria
inherit: to pass from parents to children
Common cold
Female Anopheles mosquito causes malaria. Rat flea causes plague.
to him/her as well. Some other carriers of diseases include Aedes mosquitoes (causing dengue) and rat fleas (causing plague).
Wonders of Bharat
Kerala, a beautiful state in southern India, is known for its rich history in the spice trade. Spices from Kerala have been traded with ancient civilisations across the world. These spices are packed with vitamins and minerals that boost our immune system and add a variety of nutrients to our diet.
Word Splash
nutrients: the essential components found in food that our body needs to function properly roughage: a dietary fibre that aids in digestion communicable diseases: diseases that spread from one person to another non-communicable diseases: diseases that don’t spread from person to person
Explore More!
Scan the QR code to know more about the skeletal system.
Points to Remember
• Nutrients, such as carbohydrates, proteins, fats, vitamins and minerals, are essential for the body to function properly.
• Eating a balanced diet ensures that the body gets all the essential nutrients it needs.
• Proper hygiene, regular exercise, sleep and rest are important for us to stay healthy.
• Communicable diseases spread from one person to another through various means.
• Non-communicable diseases don’t spread from one person to another.
Chapter CheckUp
1. Tick ( ) the correct option.
A. Which of the following nutrients primarily provides energy for the body?
B. Which of the following must be included in a balanced diet?
All nutrients only Nutrients with water and roughage
Only water Only roughage
C. Which of the following is a non-communicable disease?
Whooping cough Diabetes Tuberculosis Malaria
D. Which of the following is caused by consuming dirty food and water?
Dengue Malaria Plague Cholera
2. Fill in the blanks.
communicable proteins roughage water
A. helps in the growth, repair and maintenance of tissues.
B. aids in digestion and regulates body temperature.
C. helps to prevent constipation.
D. Diseases that spread from one person to another are called diseases.
3. Write True or False.
A. Good posture helps reduce strain on muscles and joints.
B. Cancer and arthritis are non-communicable diseases.
C. Exercise can help to improve our health.
D. A balanced diet means avoiding all kinds of fats.
4. Match the following.
Diseases
Caused by the deficiency of
A. Night Blindness i. iodine
B. Beriberi ii. vitamin A
C. Scurvy iii. iron
D. Rickets iv. vitamin C
E. Goitre v. vitamin D
F. Anaemia vi. vitamin B
5. Short-answer questions.
A. How do fats help the body besides providing energy?
B. What is the role of roughage in digestion?
C. Why do we need to maintain good posture?
D. Write two benefits of exercise.
E. What happens when we don’t take proper rest and sleep?
F. Why are vitamins and minerals called protective foods?
6. Long-answer questions.
A. Explain the importance of a balanced diet and how it benefits the body.
B. Differentiate between communicable and non-communicable diseases. Give examples for each.
C. Describe the different ways in which communicable diseases can spread. Give an example for each.
7. Picture-based questions.
A. Which of these actions affect the spread of communicable diseases?
B. How do actions like washing hands and covering your mouth when sneezing help prevent the spread of communicable diseases? What might happen if people don’t follow these habits?
Challenge (HOTS)
One day, during the monsoon, Latika had a plate of golgappas from a seller outside her school. The next morning, she became unwell. What do you think could have happened and why? What are the two things she should take care of to avoid falling sick like this in future?
Life Skills
Make a meal plan for yourself and your family for a week. Make sure that all the meals are balanced. Stick the meal plan on the refrigerator door or a cupboard from where it can be easily seen. Stick to the meal plan and share your experience in the class.
2 The Human Skeletal System
Chapter Overview
The Human Skeletal System
What Makes Up Our Skeletal System
Parts of the Skeletal System
Joints Muscles
Get Set
Look at the pictures of the organ systems and label them.
Circulatory system Skeletal system Digestive system Respiratory system
Our body is made of different organ systems such as the digestive, respiratory, muscular, and skeletal systems. Of these systems, the skeletal system provides shape, support and strength to our body. Let us learn more about the skeletal system.
What Makes Up Our Skeletal System
The human skeletal system is a framework of bones. It has many parts. Some of the main parts are the skull, the backbone, the ribcage, limb bones, and joints.
Bones
Bones are the hard structures that make our skeleton system. Although we cannot see them, but we can feel them as hard structures beneath our skin. They are made of calcium phosphate. A bone has three main parts:
• A hard outer layer called the compact bone.
• An inner layer called the spongy bone.
• The jelly-like material in bones is called the bone marrow. It is the site for making new blood cells. It also stores fat.
Importance
of Skeletal System
Just like a helmet protects our head against injury, similarly, our skeletal system also protects our internal organs. It also system provides support, shape and strength to the body and helps in the movement of different body parts.
Parts of the Skeletal System
Did You Know?
A newborn baby has 305 bones. Some bones fuse and an adult human is left with only 206 bones.
The main parts of the skeletal system are the skull, spine, ribcage and limbs (forelimbs and hindlimbs).
Skull
The skull is the framework of the head and it protects the brain from injuries. An adult human skull has 22 bones. All the bones of the skull, except the lower jaw, do not move and are fused together. The movable lower jaw allows us to speak and chew food. The skull has sockets for the eyes, nose and ears. Teeth are present both in the upper and the lower jaws.
sockets: holes
Think and
Spine
The spine is also called the backbone or the vertebral column. It is made up of 33 small bones called vertebrae. The vertebrae attach the skull to the spine. The spine protects the spinal cord that is present in it. The spine also allows us to stand upright, bend, stretch, twist and turn. It also helps us to maintain our balance.
Ribcage
The spine helps us bend and stretch.
Run your fingers from the underarms and move towards the waist. Do you feel some thin hard structures under the skin? These are ribs. Ribs are thin, flat and curved bones. We have 12 pairs of ribs that forms our ribcage. The function of the ribcage is to protect the heart and the lungs.
Out of 12 pairs, 10 pairs of ribs are joined to the breastbone (or sternum) in front and to the spine at the back. The last two pairs are ribs are attached only to the spine. They are not attached to the breastbone and are called floating ribs.
Limbs
Our body has two pairs of limbs. These are forelimbs, or arms, and hindlimbs, or legs.
Forelimbs
The forelimb has two parts: the upper arm and the lower arm. The upper arm has a single bone called the humerus. The lower arm has a pair of bones that are connected to the humerus at the elbow. The hand is attached to the lower arm and has many small bones.
Hindlimbs
The hindlimb has two parts: the upper leg and the lower leg. The upper leg is made of a single bone called the femur or thigh bone. The lower leg has
breastbone: a flat bone in the chest
and hindlimbs
Humerus
Forelimb
Hindlimb
Shoulder Blade Radius
Ulna
Fibula
Tibia
Femur
Forelimbs
Ball and Socket Joint
A ball-shaped end of one bone fits into the cup-shaped end of the other bone. It allows movement in many directions. Our shoulders and hips have ball and socket joints.
Pivot Joint
The pivot joint allows up, down, and side-to-side movement. It is found in our neck.
Gliding Joint
A gliding joint allows two flat bones to move past each other in any direction. The wrists and ankles have gliding joints.
Do and Learn
Sit on a chair. Your feet should touch the ground. Now move your knees in all possible directions. Now do the same for your shoulders. Which one of these moves in all directions? Which one moves only in one direction?
Immovable joints do not allow any movement. The bones at these joints are fixed and therefore they are also called fixed joints. The joints between the bones of the skull are immovable joints. They do not have cartilage between the bones.
Investigate and Discover
Fixed joints
Aim: To know the joints used to do various actions. Materials Needed: a paper, a pen, a book lying on the floor and a football Method:
Step 1: Get into groups of five.
Step 2: One student in the group to perform certain actions such as nodding, moving their head in right and left directions, lifting a book from the floor, rotating an arm, or kicking a football.
Step 3: Other students in the group will identify the joint that is being used for that action. Observe the type of movement that joint allows. Record the observations in your notebook.
Ball and socket joint
Pivot joint
Gliding joint
Findings:
1. Nodding: Pivot joint; allows up-down movement of the neck
2. Moving the head right and left: Pivot joint; allows turning the neck
3. Rotate your arm: Ball and socket joint;
4. Kick a football:
Conclusion: Joints allow movements of body parts. The range of allowed movements differs for different joints.
Muscles
Muscles are the tissues that connects two bones. They are attached to the bones by strong tissues called tendons. Our body has about 650 muscles. There are three types of muscles in our body: voluntary, involuntary and cardiac muscles.
Remember!
The muscles of our body make up the muscular system.
Voluntary Muscles
We can control the movement of voluntary muscles. Voluntary muscles are also called skeletal muscles as they are joined to our bones. They have bands or stripes and are also called striped muscles. The muscles of our arms and legs are voluntary muscles.
Involuntary Muscles
We cannot control the movements of involuntary muscles. These muscles do not have stripes on them. So, they are also called smooth muscles. The muscles in our digestive system are smooth muscles.
Cardiac Muscles
The muscles in the heart are cardiac muscles. Even though the cardiac muscles are striped, yet they are not voluntary muscles. They work continuously on their own without stopping even for a second.
Pause and Answer
Read these statements on voluntary muscles. Write T for true and F for false.
1. They are also called smooth muscles.
2. They work automatically.
3. They are present in the heart.
4. They are striped.
Wonders of Bharat
Yoga originated in India around 5,000 years ago. Maharishi Patanjali is popularly known as the ‘Father of Yoga’. He wrote a book Yoga-sutra, which talks about the different aspects of yoga. Today, 21 June is celebrated all over the world as Yoga Day.
Word Splash
bones: hard structures that make our skeleton system
bone marrow: the jelly-like material in bones
skull: the framework of the head which protects the brain from injuries vertebrae: small bones that make the spine joints: the places where two or more bones join ligaments: strong tissues that join the bones at joints cartilage: a tough elastic tissue at the surface of bones of movable joints tendons: strong tissues that join muscles to bones
Explore More!
Scan the QR code to know more about the skeletal system.
Points to Remember
• The skeletal system protects the internal organs, gives the body a shape and helps in movement.
• The human skeletal system is made up of the skull, spine, ribcage and limbs.
• Joints allow the movement of body parts. These can be movable or immovable.
• Muscles in our body are involuntary, voluntary and cardiac.
Maharishi Patanjali
Chapter Checkup
1. Tick ( ) the correct option.
A. The organ system made of bones is
Skeletal system
Digestive system
Muscular system
Circulatory system
B. Which of the following is not a part of the skeletal system? skull spine ribcage cardiac muscles
C. The number of bones in our skull is 12 22 8 33
D. The only movable bone of our skull is in the head upper jaw lower jaw collar bone
2. Fill in the blanks. cartilage ligaments ribs floating vertebrae
A. Our spine is made of small bones called .
B. The ribcage is made up 12 pairs of .
C. The ribs that are attached only to the spine are called ribs.
D. The bones are held together at the joints by strong tissues called .
E. is a tough elastic tissue that prevents the bones from rubbing against each other at the joints.
3. Write True or False.
A. The ribcage protects the heart and lungs.
B. The breastbone is also called the sternum.
C. Our spine has a total of 23 bones.
D. Our body has around 200 muscles.
4. Short-answer questions.
A. What are the functions of the skeletal system in our body?
B. What is the significance of bone marrow in our body?
C. Why is the spine important?
D. Where are immovable joints located in our body?
E. How are forelimbs different from hindlimbs?
5. Long-answer questions.
A. Describe the structure of a bone with the help of a diagram.
B. Explain the different types of joints with an example of each.
C. Differentiate between the different types of muscles. Draw their diagrams.
6. Picture-based questions.
A. Name the type of muscle marked as A.
B. Name the type of muscle marked as B.
C. Which of these muscles is involuntary?
Challenge (HOTS)
What would have happened if the muscles in our limbs were involuntary muscles?
3 The Human Nervous System
Chapter Overview
The Human Nervous System Brain Nerves Sense Organs
Get Set
Complete the following to find out the names of various organ systems.
1. This system provides shape and structure to our body.
S L T YS M
2. This system breaks down food and absorbs it.
D ES VE S T
3. This system consists of the nose, windpipe and lungs.
R S R T RY Y T
4. This system comprises of the heart, blood and the blood vessels.
I C L OR S S M
The brain, the spinal cord and the nerves constitute our nervous system. It is responsible for things like sensing and responding to stimuli. Let us learn more about our nervous system.
Remember!
An organ system consists of a group of organs that work together to perform specific functions in our body.
Brain
The brain acts as the control centre of our body. It is located in the head and is protected by the skull. It sends and receives information from all the parts of the body, through a network of nerves. The brain is further divided into three parts—cerebrum, cerebellum and medulla. Let us learn about them.
Cerebrum
Brain Spinal cord
Nerves
Human nervous system
Cerebrum
Medulla
It is the largest part of our brain. It is the in-charge of our sense organs. It gives us the capacity to think, talk, remember, recall and learn.
Cerebellum
This part of the brain is located at the back, below the cerebrum. It enables us to maintain the balance of our body, its movement and muscle coordination. Without the cerebellum, we won’t be able to stand or walk properly.
Medulla
Cerebellum
Human brain
Think and Tell
What would happen to our body movements if the cerebrum is damaged?
It is a stem-like structure which lies at the bottom of the brain. Due to its structure, it is also known as the brain stem. It connects the brain and spinal cord. It controls involuntary activities, like digestion, blood circulation and breathing. This part of the brain keeps working, even when we are asleep.
coordination: working together smoothly and efficiently involuntary: an action done without one’s own choice
Do and Learn
Make a list of any ten things that we continue doing even in sleep and ten things that we have to stop doing when we sleep. Write them a table as shown below.
Activities
Continue while sleeping Stop while sleeping
Pause and Answer
Name the following.
1. The part of the nervous system that is the control centre of the body.
2. The part of the brain that connects the brain to the spinal cord.
3. The part of the brain that helps us to maintain the body balance.
4. The largest part of the brain.
Spinal Cord
The spinal cord is a tube-like structure that extends from the medulla to the lower end of the spine. It is surrounded by the bony vertebral column. The spinal cord connects the brain to the remaining parts of the body through nerves. It also transmits information between the brain and other body parts.
Reflex Actions
The spinal cord controls some automatic and involuntary actions that do not involve the brain. Such actions are known as reflex actions. For example, when we step on something pointed by mistake, we immediately pull our feet away due to a reflex action. Some other examples of reflex action are the blinking of eyes and watering in the mouth when looking at tasty food.
transmit: to send something from one place to another
Brain
Cerebellum
Spinal cord
Nerves
Spinal cord
Reflex action
Nerves
Nerves are long, thread-like structures that transmit messages between the brain or spinal cord and other parts of the body. The nerves in the head and neck connect to the brain, while nerves from the rest of the body connect to the spinal cord. There are three types of nerves in our body: sensory nerves, motor nerves and mixed nerves. Let us learn about each of them.
Sensory Nerves
Sensory nerves carry messages from the sense organs of our body to the brain and spinal cord. These nerves help us sense the world around us. For example, when you touch something hot, the sensory nerves in your skin send a message to your brain, letting you know that it is hot.
Motor Nerves
Motor nerves carry messages from the brain and the spinal cord to the muscles in the body. These messages tell the muscles to move. For example, when you decide to pick up a book, motor nerves send a signal from your brain to your hand muscles to make them move.
Mixed Nerves
Mixed nerves have both sensory and motor nerves. This means they perform both sensory and motor functions. These nerves can carry messages to the brain or the spinal cord to other body parts and vice-versa. Mixed nerves help coordinate many activities in the body by sending and receiving messages.
Pause and Answer
Rearrange the following to make meaningful words related to the nervous system.
Sense Organs
Our sense organs are special organs in our body that help us experience the world around us. They allow us to see, hear, smell, taste, and feel. These organs collect and send information to our nervous system through sensory nerves. Our brain further processes the information and lets us know about what are we experiencing through
our sense organs. There are five sense organs in our body—eyes, ears, nose, tongue and skin. Let’s learn about them.
Eyes
Eyes help us see different things around us. They are very sensitive organs. Therefore, these are protected by eyelids and eyelashes from dust, dirt and bright light. Our eyes are complex organs and have many parts. Let us learn about them.
Parts of the Eye
Cornea: It is a thin transparent layer that covers and protects the front part of the eye.
Iris: It is the round and coloured part that lies behind the corner of the eye. It can be blue, black, brown or grey.
The lens: The transparent part of the iris. It is located behind the iris.
Pupil: It is the black spot in the centre of the eye that lets light in.
Retina: It is a thin lining present at the back of the eye. It is like a screen. The retina is connected to the brain through optic nerves. These nerves send signals to the brain, which then interprets the signals as images.
Ears
Did You Know?
The size of the pupil depends on the brightness of light entering our eyes. The pupil becomes bigger in dim or low light. On the other hand, the pupil becomes smaller in bright light.
Our ears allow us to hear sounds. Each ear is divided into three parts: the outer, middle and inner ear. The outer and visible part of the ear is called the pinna. It receives sound and directs it to the eardrum through the ear canal. The eardrum is located in the middle ear.
The middle ear is composed of three small bones, including the eardrum, that transmit sound waves to the inner ear.
The inner ear converts these sound waves into nerve signals and sends them to the brain via the auditory nerve. The brain then interprets these nerve signals, allowing us to hear different sounds.
interpret: to understand information auditory: related to hearing
Iris Cornea Pupil
Lens
Retina Optic nerve
Human eye
Outer ear
Pinna
Eardrum
Inner ear
Middle ear
Ear canal
Human ear
Middle ear
Tongue
The tongue helps us speak, and taste a variety of food. The surface of our tongue is covered with many taste buds. The taste buds send signals to the brain, which then interprets these signals as different tastes. Our taste buds can detect four major tastes: sweet, sour, salty and bitter.
Discuss!
How would it be if we had no taste buds present on our tongue? Discuss with your classmates.
Nose
Our nose helps us smell and breathe. It has two openings called nostrils. Inside the nostrils, tiny hairs and mucus trap dust particles. Our nose has special nerve cells that detect different smells and send messages to the brain. The brain then interprets these messages, allowing us to recognise what we are smelling.
Skin
The skin is our largest sense organ. There are many nerve endings in the skin that help us feel touch and sensations like hotness, coldness and pain. The skin has different types of receptors that detect different sensations. Our skin also has pores on its surface that allow body waste to exit as sweat. Besides protecting our internal organs, our skin also helps to regulate body temperature.
Investigate and Discover
Experiment: To demonstrate how the tongue helps us identify different tastes.
Materials Needed: Food items cut into pieces (apple, cucumber, carrot, mango, peach, pear, lemon) and a blindfold
Step 1: You can do this experiment with a friend or a family member. Arrange the different food items on a table.
Step 2: Ask your friend or the family member to volunteer to be blindfolded. Then, let him/her taste one item at a time. Make sure you give the person enough time to taste the item properly.
Step 3: Ask him/her to guess the taste of the food item and then its name.
recognise: to identify sensation: a type of feeling
Nose
Tongue
Step 4: You can volunteer to be blindfolded and taste a different set of food items.
Findings: We can identify the taste of different food items without actually seeing what food it is.
Conclusion: Our tongue helps us taste various food items.
Tip: Please arrange different food items per their availability.
Taking Care of Our Sense Organs
Our sense organs are essential for experiencing the world around us. They help us see, hear, smell, taste and feel. It’s important to take good care of them for their proper functioning. Here are some tips on how to take care of each of our five sense organs.
Eyes
• Avoid staring at screens for too long. Take breaks every 20 minutes to rest your eyes.
• Maintain a proper distance while watching computer screens or TV.
• Avoid reading in dim lights or while travelling when the book.
• Don’t touch your eyes with dirty hands. Wash your hands before touching your eyes.
Ears
• Clean the outer part of your ears with a damp cloth.
• Never put sharp objects inside your ears.
• Don’t listen to loud music for too long. Plug your ears with your fingers if you are in a noisy place.
• If you have trouble hearing, visit a doctor as soon as possible.
Nose
• Gently blow your nose to clear out mucus and dust. Don’t pick your nose.
• Stay away from strong chemicals and smoke that can irritate your nose.
Tongue
• Always clean your tongue using a tongue cleaner.
• Don’t eat foods which are too hot as they can burn your tongue.
Skin
• Bathe regularly with mild soap and water to remove dirt and sweat.
• Always wear clean and washed clothes.
• Eat raw fruits and vegetables and plenty of water to keep your skin healthy.
• Keep any open cut or wound away from dust and dirt and ask an adult to put an antiseptic cream on it.
damp: slightly wet or moist
Wonders of Bharat
The Garden of Five Senses in Delhi is designed to stimulate all our sense organs through visually appealing flowers, fragrant plants, and different textures to touch. It also offers sounds from nature, creating a joyful experience that engages our sight, smell, touch, hearing and taste.
Word Splash
nerves: long thread-like structures that carry messages between the brain, spinal cord and the other parts of the body
reflex actions: involuntary actions that are automatic and in which the brain is not involved nostrils: two openings present on the nose receptors: special cells in our body that detect and respond to different types of signals, like light, sound or touch lens: the transparent part of the iris
Explore More!
Scan the QR code to know more about brain.
Points to Remember
• The nervous system comprises the brain, spinal cord and nerves.
• The brain is the control centre of the body.
• The spinal cord is a tube like structure consisting of nerves that runs from the brain to the lower spine, transmitting information between the brain and the body.
• Nerves are thread-like structures that carry messages between the brain, spinal cord and the body.
• Sense organs help us experience the world. There are five sense organs in our body—eyes (seeing), ears (hearing), nose (smelling), tongue (tasting) and skin (feeling).
Chapter Checkup
1. Tick ( ) the correct option.
A. Where is the brain located and how is it protected?
In the chest, protected by ribs
In the head, protected by the skull
In the abdomen, protected by muscles
In the neck, protected by bones.
B. What is the function of motor nerves?
Carry messages from the body to the brain
Carry messages from the brain to the body
Carry messages from the brain to the spinal cord
Control movement of the body parts
C. What do our sense organs help us do?
Move our muscles
Experience the world around us
Digest food
Grow
D. What is the function of the nose besides smelling?
Tasting
Breathing
2. Fill in the blanks.
Hearing
Seeing
A. The connects the brain to the remaining parts of the body through nerves.
B. nerves carry messages from the sense organs to the brain and spinal cord.
C. nerves carry messages from the brain and spinal cord to the muscles in the body.
D. The surface of our tongue is covered with many buds that detect different tastes.
3. Write True or False.
A. The cerebellum is the largest part of the brain.
B. There are only two types of nerves in our body.
C. Mixed nerves have both sensory and motor nerves.
D. The spinal cord transmits information between the brain and other body parts.
4. Match the following.
A. eyes
B. ears
C. nose
D. skin
E. tongue
5. Short-answer questions.
A. Why is the nervous system important?
i. sight
ii. taste
iii. smell
iv. sensation
v. hearing
B. How are sensory nerves different from motor nerves?
C. Write two ways to take care of your skin.
D. Which part of the nervous system is responsible for reflex actions?
E. Name and describe three parts of the eye.
6. Long-answer questions.
A. Describe the main parts of the brain. Mention the function of each part.
B. Describe reflex action with an example.
C. Explain how motor nerves help us move our muscles with the help of an example.
D. Draw and describe the three parts of the ear and their functions.
7. Picture-based questions.
A. What is shown in the image?
B. Label the parts in the image.
C. Mention the function of the part labelled as 2.
Challenge (HOTS)
Which parts of the nervous system work together to make us wake up in the morning?
Life Skills
Think about a friend you know who might have trouble seeing or hearing well. List some activities where this friend might find it hard to do things because of their vision or hearing issues. Write down some ideas on how you can help this friend make these activities easier for them. Offer to help your friend and share your ideas with others to encourage them to be supportive too.
4 Safety and First Aid
Chapter Overview
Safety and First Aid
Importance of Safety Safety on Roads First Aid
Safety at Home
Solve the following riddles. INTEGRATED Get Set
I am in your car and keep you tight, If there’s a sudden stop, I hold you right. Put me on before you start, For safety’s sake, I’m a crucial part.
What am I?
I protect your head and keep it sound. When you’re riding your bike around Strap me on before you go. For safety first, that’s what you should know.
What am I?
Importance of Safety
We should always be alert and aware to decrease the chances of accidents. An accident is an unexpected event that causes harm, injury or damage. Accidents can occur if we are not cautious. To prevent accidents and ensure our safety, it is important to follow certain safety rules. Let us learn more about them in this chapter.
Basic Rules of Safety
• Always cross the road at the zebra crossing. Look both ways before crossing the street.
• Do not run up or down the staircase.
• Do not play with sharp objects, fire, electrical appliances.
• Whenever there is an accident, help the injured. Don’t panic in such situations.
Use zebra crossing to cross roads.
Safety at Home
Think and Tell
Imagine you are responsible for creating a safety plan for a school field trip. What are the key safety measures that you would include?
We spend a lot of time at home, so it is very important to follow safety rules to stay safe. Let us discuss different situations where we need to be cautious while at home.
Sharp Objects
Have you ever seen anyone cutting fruits and vegetables with a knife? They always cut them very carefully to avoid any injury.
To stay safe while handling sharp objects, follow the following rules:
• If you are carrying scissors, keep the sharp sides pointing downwards. Use sharp objects under adult supervision.
alert: fully aware cautious: being careful
• Never run while holding a sharp object.
• Keep all sharp objects away from children.
• Be careful with your fingers when using a knife. Do it under adult supervision only.
Electrical Appliances
We need to be careful while using electrical appliances. To be safe around such appliances, follow these rules:
• Do not use electrical appliances with wet hands.
• Always operate them under adult supervision.
• Wear rubber slippers when handling them.
• Avoid plugging too many devices into a single socket, as it may lead to a short circuit and cause a fire.
Gas Leak
Sharad noticed a peculiar smell coming from the gas stove. He quickly called his father. His father asked Sharad to stay away and quickly turned the gas cylinder off.
The gas cylinders have an added smell in them that makes the detection of gas leaks easy. In case of a gas leak, follow the steps mentioned below.
• Warn everyone in the house about the leak.
• Open all the doors and windows to let the smell out.
• Don’t operate any electrical appliances, as these can produce sparks.
• Call the gas company or mechanic immediately to repair the leak.
Fire
In case of a fire, follow the steps given below:
• Inform an adult and immediately call the fire brigade.
• If the fire is at a plug point, do not throw water on it. Either use the fire extinguisher or sand.
supervision: monitoring of someone over an activity peculiar: strange
Use a fire extinguisher to control fire.
Never touch electrical appliances with wet hands.
Open windows in case of gas leaks.
• If the fire is due to oil or petrol, again, use the fire extinguisher instead of water.
• If the fire is out of control, immediately evacuate that area.
Chemicals
We use chemicals, like detergents and disinfectants, in our homes. Some chemicals, like vinegar and baking soda, are also used in cooking. We also keep medicines at home for emergencies. To stay safe around these things, follow these rules:
• Always keep chemicals and medicines out of the reach of children.
• Take all medicines only under adult supervision.
Wear gloves while using chemicals.
• Always wear gloves while handling chemicals like disinfectants and floor cleaners.
• Wash your hands thoroughly after handling chemicals, even if you were wearing gloves.
• Seek medical help immediately if you accidentally swallow chemicals or get them in your eyes.
Internet Safety
Nowadays, the internet plays a crucial role in our daily lives, including helping with homework and projects. However, it is essential to follow certain guidelines to ensure online safety.
• Never share your personal details online without your parents’ permission.
• Create strong, unique passwords for your online accounts and don’t share them with anyone.
• Only chat with people you know in real life.
• Spend a balanced period of time online.
Pause and Answer
Tick ( ) the correct statement about internet safety.
1. We should share our personal details with an unknown person.
2. We should spend a balanced period of time online.
3. We should share passwords with everyone.
4. We should chat with everyone.
evacuate: to leave an area urgently unique: different from others
Safety on Roads
Ravi is riding his bike on the footpath. He has a helmet on to protect his head. As he rides, he makes sure to stay on the footpath and look both ways before crossing the lane. Why is it essential to wear a helmet? A helmet helps to protect your head if you fall or bump into something. Without it, Ravi could hurt himself more easily. Wearing a helmet keeps you safe while riding your bike! Let us learn more about road safety.
To be safe on roads, follow these rules:
Always wear helmet while riding bicycle.
• Look left and right before crossing. Wait for the traffic to come to a complete stop before crossing.
• Obey traffic signals and road signs. Green means go, red means stop and yellow means prepare to stop.
• Don’t jump off or get on moving vehicles.
• Never stick your hands or face out of a moving vehicle.
• Don’t play near roads. Play in parks or playgrounds instead.
Do and Learn
Many think only drivers need to follow traffic rules, but that’s not true. Cyclists and pedestrians must also follow road-crossing rules. Error Alert!
Make some posters showing road signs for display in your classroom. You can discuss their importance with your teachers, school bus drivers and your parents.
First Aid
Since accidents can happen anywhere and anytime, it is wise to know what to do during an emergency. First aid is the immediate help given to someone who is hurt or sick before a doctor can attend to it.
Cuts and Wounds
The following first-aid measures should be taken in case of a cut or wound.
Never keep your body parts out of the moving vehicle.
• Cuts and wounds can happen at any time, and knowing how to provide first aid is essential for proper care and healing.
• Never ignore a wound, no matter how small it seems. Keep hygiene in mind when giving first aid, as germs can easily enter through cuts.
Remember!
An ice pack is a bag filled with ice or a cold substance used to reduce swelling and pain from injuries.
• Wash your hands with soap and water before treating a wound.
• Clean the wound with water, soap, and antiseptic lotion.
• Cover it with a bandage to prevent infection and control bleeding.
• If the bleeding continues, apply a tight bandage above the wound to reduce heavy bleeding.
• For deep wounds, take the person to a doctor immediately, as stitches may be needed. If the cut is from a rusty object, an anti-tetanus injection may be necessary to prevent tetanus.
Burns
Burns can be caused by touching something hot, like a stove or a flame, hot liquids like boiling water or steam and chemicals.
• If a person’s clothes catch fire, tell them to lie down and roll on the ground to extinguish the flames, as fire spreads upward.
For minor burns, run cool water over it
• Wrap the person in a blanket to cut off the air supply and put out the fire.
• The person should not run, as this will fan the flames and make the fire spread.
• Do not apply ointment or cream to burns.
• For minor burns, run cool water over it. Apply an antiseptic cream over the burn.
• For serious burns, cover the area with sterile gauze and a loose bandage.
• Avoid puncturing any blisters.
Fracture or Sprain
A fracture occurs when there is a crack in the bone. Use a splint to prevent the moving of the fractured part. Seek medical help immediately.
A sprain indicates an injury to the ligament. A ligament is the tissue connecting the bones at the joints. When a ligament is torn or stretched, it causes sprain. This usually occurs due to falling or twisting.
Use a splint in case of a fracture.
blister: small bubble formed on the skin due to burns (usually have water in it) splint: a stiff support used to keep broken bone in place
• Keep the injured joint still to avoid any other injury.
• Apply an ice pack over the injured area to reduce swelling. Keep it on for at least 15 minutes.
• Wrap the injured part with an elastic bandage to provide support.
• Raise the injured part above the level of the heart to reduce swelling.
Nose Bleed
On hot, dry days, a nosebleed may occur when tiny blood vessels in the nose burst. The following first-aid measures should be taken in case of a nose bleed:
• Loosen clothing around the neck.
• Have the person sit upright with their head slightly forward.
• Pinch the bleeding side of the nose and ask the person to breathe through their mouth.
• Apply an ice pack or wet cloth to the nose and neck.
• Advise the person not to blow their nose for a few hours after the bleeding stops.
• If the bleeding is heavy, consult a doctor immediately.
Dehydration
Dehydration happens when your body loses more water than it takes in. This can happen if you don’t drink enough water, especially on hot days or after lots of exercise. Signs of dehydration include feeling thirsty, tired, dizzy, or having a dry mouth.
• Give the person small sips of water or an oral rehydration solution (ORS) to drink.
• Move the person to a cool, shaded area to rest.
• If the person feels very weak or dizzy, seek medical help immediately.
Insect Bites
Insect bites or stings can be very painful. It can cause redness, swelling and itching in the affected area.
• Wash the bite area with soap and water. Use an antiseptic lotion over the infected area. Remove the insect sting with the help of a tweezer.
• For a bee sting, apply toothpaste or sting relief cream over the bite area.
A woman pinching her nose and leaning forward, in a nose bleed.
Sting relief cream provides relief from bee sting.
Ice pack prevents swelling in sprains.
Did You Know?
For a snake bite, tightly tie a cloth above the bite area. This will prevent bleeding and the spreading of poison in the body. Seek medical help immediately.
Wonders of Bharat
Traditional remedies, such as using Neem leaves for insect bites, are helpful for first aid. Neem has antiseptic, anti-inflammatory, and antibacterial properties that can reduce itching and prevent infection. It is still commonly used as a natural solution for insect bites.
Word Splash
first aid: the immediate help given to someone who is hurt or sick before a doctor can take over fracture: a crack in the bone sprain: when a ligament gets torn or stretched, it causes sprains
Explore More!
Scan the QR code to know more about first aid.
Points to Remember
• Accidents can happen with anyone and at any time.
• We should always be alert and aware to prevent accidents.
• In case of accidents, first aid measures should be followed.
• Stay calm and help the patient in case of an accident till the doctor arrives.
Chapter Checkup
1. Tick ( ) the correct option.
A. What should you do if you burn yourself slightly?
Apply ice directly on the burn Run cool (not cold) water over the burn
Cover it with a heavy cloth
Pop any blisters that form
B. Why is it important to wear a helmet while riding a bicycle?
To look fashionable
To protect your head in case of an accident
To ride faster
To keep your hair in place
C. When crossing the road, what should you always do?
Run quickly across Look left and right first Cross at any point you like Follow the car ahead of you
D. Which of the following is a sign of dehydration?
Sweating
Dizziness
2. Fill in the blanks.
Increased urination
Feeling energetic
A. An is an unexpected event that causes harm, injury or damage.
B. A is a break or crack in the bone.
C. happens when our body loses more water than it takes in.
D. Use creams to prevent infection.
3. Write True or False.
A. You should perform first aid before calling for medical help in an emergency.
B. Pedestrians should follow traffic signals, just like vehicles.
C. Leaning your head back is the best way to stop a nosebleed.
D. It’s okay to ignore an insect bite and not wash the area.
4. Short-answer questions.
A. Write any two ways to stay safe on the road.
B. What should be done in case of a kitchen fire?
C. Mention the first aid to be given in case of dehydration.
D. How can you help someone with an insect bite?
E. Write two ways that you should follow for internet safety.
5. Long-answer questions.
A. What is an accident? Why should we follow safety rules?
B. How would you provide help to a person with a nosebleed?
C. What precautions should you take when handling medicines and chemicals?
6. Picture-based questions.
A. What kind of an accident is shown in the given image?
B. Mention the first aid to be given in this case.
Challenge (HOTS)
If a family member gets a deep cut while using a sharp tool at home, what immediate actions would you take to stop the bleeding and prevent infection?
Life Skills
In small groups, choose a common household accident, such as burns, cuts, or electric shocks. Each group will act out how to give first aid for that situation and follow safety rules. After the role-play, discuss how to prevent such accidents and why staying calm is important during emergencies. This activity helps everyone understand the steps needed to stay safe and handle emergencies at home.
Natural Calamities
Chapter Overview
Natural Calamities
Types of Calamities
Dealing with Calamities
Get Set
Solve the following riddles.
I am round with many layers, not a fruit or a treat. I spin through space, yet you stand on your feet.
What am I?
Introduction
I have no colour, but I am everywhere, I fill the oceans and float in the air.
What am I?
It was a regular school day, and Siya was enjoying her science class. Then, it started raining heavily, and the rain kept getting stronger. The principal announced that school would end early because of flooding in many places. Siya wanted to learn more about flooding, so she asked her teacher. The teacher explained to her that flooding is a type of natural calamity. Let us learn more about natural calamities. A natural calamity is a sudden event caused by natural forces that can cause a lot of damage to the environment, life and property.
Types of Calamities
Some common natural calamities are earthquakes, volcanoes, tsunamis, floods, cyclones and droughts. Let us learn about each of them in detail.
Earthquake
An earthquake occurs when the ground shakes suddenly. Earthquake is also called as tremor or quake.
Cause of an Earthquake
An earthquake is a sudden shaking of the Earth’s surface caused by movements within the Earth. The Earth’s crust consists of large and small rock plates called tectonic plates that move slowly past each other. Sometimes, these plates pull apart, collide, or slide under one another, causing vibrations that result in earthquakes. They can range from mild to severe, leading to significant damage to life and property.
The point on the Earth’s surface directly above where the earthquake starts is called the epicenter, which feels the strongest effects. The focus is the point below the ground at which the earthquake originates. Aftershocks are smaller tremors that may occur within a few days after the main quake as the rocks settle back into place.
Earthquakes are measured with a seismograph, and their intensity is recorded on the Richter scale. Richter scale was developed by Charles Richter in 1935. Earthquakes rated between 6 and 8 on this scale can cause major destruction, with the extent of damage depending on the earthquake’s location and intensity. A value of 1 on the Richter scale indicates a minor earthquake.
Effects of an Earthquake
• An earthquake can cause the ground to vibrate and shake which leads to the collapsing of buildings, roads and bridges.
• Many people lose their lives as they get trapped under the collapsing buildings.
• The shaking ground during an earthquake can crack gas pipes, leading to fires. This results in more damage to the people and buildings.
intensity: strength or force of something
Effects of earthquake
An earthquake struck site
A seismograph
Preventive Measures
• If you are indoors, cover your head and neck with your arms. Take shelter under a sturdy piece of furniture, like a table or desk.
• If you are outside, stay away from tall buildings, trees and power lines. Move to an open space such as a field or park.
• If you are inside a tall building, evacuate it as soon as possible.
Take shelter under a piece of furniture.
• Do not use elevators during an earthquake as they may get stuck or malfunction. Instead, take the stairs.
Gather information about the Bhuj earthquake that occurred in 2001. You may take help of the internet or an adult. Make a report of it in your scrapbook. Collect and paste pictures and news clippings related to this disaster to make your report more informative.
Pause and Answer
Name the following.
Discuss!
Discuss how families and schools can prepare for an earthquake. What should be included in an emergency kit? Where are the safest places to take cover?
1. Instrument used to measure the intensity of an earthquake.
2. Scientists who study and observe earthquakes.
3. Small tremors felt after the earthquake.
4. Large plates of rocks that make up the earth’s crust.
Do and Learn Volcano
A volcano is an opening in the earth’s surface through which molten rock called magma comes out . When this magma reaches the earth’s surface, it is called lava. It comes from the inner layers of the earth and reaches the outer layer through cracks. Eruptions happen when pressure builds up inside the earth. Eruption of volcanoes can cause a lot of damage to life and property. It is difficult to control such type of natural calamity.
sturdy: strong; malfunction: to function incorrectly; magma: hot, melted rock found beneath the Earth’s surface; lava: hot, melted rock that comes out of a volcano during an eruption; eruptions: sudden explosion
Types of Volcanoes
Active volcano: These volcanoes can erupt at any time or have erupted recently. For example, Barren Island in Andaman and Nicobar islands, Mount Vesuvius and Mount Fuji.
Dormant volcano: A volcano that has not erupted in recent years but can erupt in the near future is known as a dormant volcano. For example, Mount Kilimanjaro in Tanzania and Mauna Kea in Hawaii.
Extinct volcano: Volcanoes that have stopped erupting and have no chances of erupting in the future are known as extinct volcanoes. For example, Mount Popa in Myanmar and Zuidwal volcano in the Netherlands.
Tsunami
Tides are the regular rise and fall of sea levels caused by the pull of the moon and the sun. When the Sun, the Moon, and Earth are in a straight line, tides can be higher than usual. Tidal waves can occur due to storms or earthquakes.
Tsunamis are very large waves caused by underwater earthquakes or volcanic eruptions. The term “tsunami” means “harbor wave” in Japanese and is often confused with tidal waves. When a tsunami occurs, the waves can travel in all directions and can reach heights of up to 100 feet when they reach the shore, causing massive destruction in seconds.
While tidal waves and tsunamis cannot be controlled, people can be advised to move to higher ground for safety. Many coastal areas have tsunami warning centers that help alert residents about potential tsunamis.
Did You Know?
The Indian Ocean tsunami was triggered by a massive undersea earthquake off the coast of Sumatra, Indonesia, on December 26, 2004. The tsunami measured 9.1 on the Richter scale. Sri Lanka, India, Maldives, Somalia and Thailand were the countries affected by the tsunami.
Tsunami
Floods and Cyclones
Floods happen when a river overflows its banks. Heavy rainfall is the major cause of floods. When air pressure in coastal areas changes, it causes sudden strong storms. These are called cyclones, typhoons, hurricanes or tropical storms, depending on their locations.
These storms bring heavy rain, strong winds and can cause big waves. These can be dangerous and affect coastal areas, causing damage to homes, trees and sometimes flooding.
Effects of Floods and Cyclones
• Both these disasters cause damage to life and property.
• Floods wash away the crops and destroy them.
• Floods result in water logging, which affects traffic movements and causes diseases such as cholera, dengue, typhoid and malaria.
Preventive
Measures
• Floods can be prevented by building, checking and maintaining dams regularly.
• We should construct raised embankments or bunds near residential areas to prevent the overflow of water.
• We should plant trees along river banks to avoid the overflow of water.
• To prepare for cyclones, early warning system that alerts coastal areas about approaching storms should be maintained.:
Investigate and Discover
Aim: To show how flooding affects different surfaces.
Materials Needed: Two trays, soil, stones or grass (for one tray), water, and a watering can or cup.
Method:
Step 1: Fill both trays with soil. In one tray, add stones or grass on top of the soil. Leave the other tray with just soil.
Step 2: Slowly pour water over both trays to depict heavy rain or a flood.
water logging: collection of too much water on the ground embankments: raised barrier or mound built to prevent flooding or support roads and railways
A car in a flooded street
Cyclone Dams prevent floods
Step 3: Observe how the water affects both trays.
Findings: The tray with only soil shows more erosion and water runoff. The tray with stones or grass shows less soil movement and more water absorption.
Conclusion: Natural coverings like grasses and stones help reduce the effects of floods by preventing soil erosion and controlling water flow. This shows how important it is to protect the environment to reduce the impact of floods.
Drought
A drought occurs when a region receives little to no rainfall for an extended period, sometimes lasting for years. This leads to higher temperatures and shortages of food and water.
Effects of Drought
• It dries up water bodies, making it difficult to grow crops. This causes great problems for farmers and other people.
• If drought lasts for a longer period of time, famines can occur due to food shortage. Deforestation can reduce rainfall and create drought-like conditions. In India, regions such as eastern and southern Maharashtra, northern Karnataka, Andhra Pradesh, Odisha, Gujarat, Telangana, and Rajasthan are prone to drought.
Preventive Measures
• Plant more and more trees in our surroundings.
• Save water by using it wisely at home and in agriculture.
• Planting crops that need less water to grow.
• Communities can also build reservoirs to store water during rainy seasons to use during dry periods. This practice is called rainwater harvesting.
A common misconception about droughts is that they are just short periods without rain. In reality, droughts can last for months or even years, severely impacting water availability.
By studying how natural calamities like earthquakes, floods and droughts occur, we learn to ask important questions and find solutions to protect ourselves. This careful observation helps us better prepare for and respond to such events.
famines: extreme scarcity of food reservoirs: artificial lakes made to store water
Error Alert!
Pause and Answer
Match the natural disasters with their respective causes.
Natural disasters Causes
1. Volcanoes
2. Earthquakes
3. Droughts
4. Floods
5. Tsunamis
A. Causes excessive shaking of the ground
B. Caused by eruption of molten lava
C. Caused by heavy rainfall
D. Caused by less rainfall and water scarcity
E. Caused by underwater earthquake
Dealing with Calamities
We cannot predict or control natural calamities. But we can be prepared beforehand for any such disaster. We should spread awareness about these calamities.
Although we cannot control the disasters from happening, we can help the victims in many ways. We can donate money, clothes, food items and other essential supplies to the disaster-affected people.
Help from Government
• Early Warning Systems: Use weather monitoring and forecasting to predict floods and cyclones early.
• Community Preparedness : Educate people about the risks of natural calamities and what to do in emergencies, such as conducting mock drills.
• Evacuation plans: This include taking measures to lead people out of danger and take them to safe places.
NGOs and Other Organisations
NGOs are Non-Governmental Organisations that provide help to victims. One of the well-known NGOs is the Red Cross society. Other organisations that work towards public welfare are WHO and UNICEF. Let us discuss how each of them helps the disaster-hit victims.
Remember!
Human beings should help each other in times of crisis.
forecasting: guessing or predicting; emergencies: sudden and unexpected situations
Evacuation camps
Red Cross Society relief camp
1. Red Cross Society: It is an organisation that helps people in emergencies, like natural disasters or accidents. It provides food, shelter and medical care to those in need.
2. WHO (World Health Organization): They help countries by giving advice on how to prevent and treat diseases, and they also help during health emergencies like outbreaks of new diseases.
Think and Tell
List any two ways in which you can help the disaster-hit victims.
3. UNICEF (United Nations International Children’s Emergency Fund): It is an organisation that helps children all around the world. They work to make sure that every child has what they need to grow up healthy and happy.
Wonders of Bharat
The Sundarbans, located in the delta region of West Bengal, are the largest mangrove forests in the world. These mangroves act as a natural shield against natural calamities like cyclones. When a cyclone hits, the dense mangrove roots and trees help absorb the impact of strong winds and waves, reducing the damage to nearby areas. Sunderbans
Word Splash
natural calamity: a sudden event caused by natural forces that can cause widespread damage earthquake: the sudden and violent shaking of the ground epicenter: the point on the Earth’s surface directly above where the earthquake starts volcano: a mountain that erupts to let out to a pool of molten rock (magma) from below the Earth’s surface floods: a situation when too much water covers land
Explore More!
Scan the QR code to know more about natural disasters.
Points to Remember
• Natural calamities can cause widespread destruction to the environment.
• Some of the common natural calamities include earthquakes, volcanoes, tsunamis, floods, cyclones and droughts.
• We can donate money, clothes and other essential stuff to the calamity-affected people.
• The government and the NGO’s play an important role in disaster management.
Chapter Checkup
1. Tick ( ) the correct option.
A. Which of these values on the Richter scale indicates a mild earthquake?
1 7 9 8
B. How many types of volcanoes are there?
Two Three Four Five
C. Which of these is a common effect of drought?
Flooding Water scarcity Strong winds Earthquakes
D. What should you do during an earthquake?
Run outside immediately.
Stand near windows.
Take cover under a sturdy piece of furniture.
Use the elevator to get to a higher floor.
2. Fill in the blanks.
A. The intensity of an earthquake is measured by an instrument called .
B. There are types of volcanoes in nature.
C. is a hot, melted rock found beneath the Earth’s surface.
D. can be prevented by building dams.
E. A is a huge ocean wave caused by underwater earthquakes or volcanic eruptions.
3. Write True or False.
A. NGO’s do not have any role to play in dealing with calamities.
B. It is important to have early warning systems in place to deal with a natural calamity.
C. Active volcanoes can erupt at any time.
D. The Richter scale is used to measure the intensity of an earthquake.
E. We should use the elevator during an earthquake.
4. Short-answer questions.
A. What causes earthquakes?
B. How do we measure earthquakes?
C. How can we prevent floods?
D. What happens during a drought?
E. Name any three organisations that help disaster-hit victims.
5. Long-answer questions.
A. Explain different types of volcanoes with an example of each.
B. What are the preventive measures implemented by the government to deal with natural calamities?
C. What is a drought? Mention any two causes of droughts and two measure that can be taken to prevent droughts.
6. Picture-based questions.
A. Identify and name the natural calamity shown in the image.
B. What happens during this calamity?
Challenge (HOTS)
Imagine you are part of a disaster management team in your town. Discuss three strategies you would propose to improve community preparedness for natural disasters like floods or earthquakes.
Life Skills
We can help people affected by natural calamities in many ways. Collecting and giving relief materials like food, water, and clothes is important. Organising fundraisers and donating money to trusted groups can support their recovery. Volunteering to help distribute supplies or offer shelter also makes a big difference. Raising awareness through social media and creating care packages with essentials like food and blankets can bring comfort to families in need. Together, we can help rebuild communities after a disaster.
Serving food for the needy
PROJECT 1 Homemade Volcanic Eruptions!
Objective: Students will understand how a volcano erupts.
Materials Needed: A small bottle, baking soda, vinegar, red food colouring, clay, a cup, a tablespoon and a tray
Step 1: Learn about Volcano and Their Different Types: Study about the volcano and its various types. You can take the help of school textbooks or the internet.
Step 2: Build Your Volcano: Place the plastic bottle in the centre of the tray. Shape clay around the bottle to create a volcano, leaving the top open.
Step 3: Prepare the Eruption:
• Add two tablespoons of baking soda to the bottle.
• In a separate cup, mix ½ cup of vinegar with a few drops of red food colouring.
Step 4: Erupt the Volcano: Carefully pour the vinegar mixture into the bottle and watch the eruption!
Tip: Take the help of an adult while pouring the vinegar mixture into the bottle.
Step 5: Document Your Observations: Take pictures of or draw each step of your project, especially the eruption. Write down what happened and any similarities to real volcanoes.
Project Output: Now you have your own volcano model. Share your volcano model and pictures with the class. Explain how it works and what you learnt about volcanic eruptions.
Final Outcome: This hands-on project not only allows you to create a fun and exciting volcano model but also helps you understand the scientific principles behind volcanic eruptions and encourages teamwork, observation and communication skills.
To be read aloud and explained in the mother tongue by the teacher, as needed.
Assessment 1
Read the given conversation. Answer the questions given below.
Internet Safety!
Aarav: Hi, Meera! I just got a new game on my computer. I can even chat with people while playing!
Meera: That sounds fun, Aarav! But remember, we need to be careful when talking to people online.
Aarav: Why? It’s just a game.
Meera: Well, some people online might not be who they say they are. It’s important to only talk to people you know in real life like friends or family.
Aarav: Oh, I didn’t think about that. What else should I do to stay safe?
Meera: Make sure you have a strong password and never share it with anyone. Also, don’t click on links or download anything from people you don’t know. It could be dangerous.
Aarav: Good idea! I’ll be careful. What if I see something weird or someone is mean to me?
Meera: You should tell a trusted adult, such as your parents or a teacher, right away. They can help you report it, if needed.
Aarav: Thanks, Meera! I’ll remember these tips to stay safe online.
1. Which of the following is a good practice to stay safe while using the internet?
A. Sharing your full name and address with friends online
B. Using a strong password and not sharing it with anyone
C. Clicking on any link you find interesting
2. What should you do if you see something online that makes you feel uncomfortable?
A. Ignore it and continue using the internet
B. Click on it to learn more about it
C. Report it to a trusted adult
3. Imagine you are playing an online game and someone you don’t know sends you a message. Mention any two steps you would take to ensure your safety.
4. Aarav is excited to play his new game online, but he is asked to create a password. What are some important things Aarav should keep in mind while creating his password, and why is it important to have a strong password?
To be read aloud and explained in the mother tongue by the teacher, as needed.
Reproduction in Plants
Chapter Overview
Reproduction in Plants
Flower: A Reproductive Part
Growing Plants from Seeds
Growing Plants from Roots
Growing Plants from Stems
Growing Plants from Leaves Agriculture
Get Set
Write the names of these parts of a plant. Do you know their functions?
Look at the plants around you, you will see that some have flowers while others do not. Flowers often have bright colours and pleasant smell, and some of them eventually turn into fruits. Fruits such as apples, oranges and papaya, contain seeds inside. We plant seeds in the soil, and they then grow into new plants. However, some plants can be grown without seeds. Plants reproduce in two ways:
• through seeds
• through roots, stems and leaves
Flower: A Reproductive Part
When you walk through a garden, the first thing that catches your eye is usually the colourful, fragrant flowers. Each flower is unique in size, shape, colour and scent. These flowers play a vital role in a plant’s life. They serve two purposes:
• To attract insects that aid in pollination
• To form seeds that will develop into new plants
Parts of a Flower
Sepals: These are small, green, leaf-like structures which protect the flower when it is still a bud. Generally, sepals are green in colour.
Petals: These are brightly coloured and vary enormously in shape. The main function of the petals is to attract insects and birds to the flower.
Stamens: The stamen is located within the flower. It is the male reproductive part of the flower. Each stamen consists of a long filament with an anther at the top. The anther contains pollen grains.
Carpels: The carpel is the central part of the flower. It is also known as pistil. It is the female part of the flower contains a stigma, a style and an ovary. The style connects the stigma to the ovary, which contains one or more ovules that later become seeds.
Do and Learn
Take a hibiscus or any other flower, carefully dissect it, and observe its different parts.
Parts of a flower
Stigma
Petal
Style
Carpel
Ovary
Ovule
How Seeds are Formed
Plants reproduce in a fascinating way to create new life. One important process in this is seed formation, which involves several steps. Here is how seeds are formed:
• For a seed to form, pollen must travel from the anther to the pistil and then down to the ovary. You may have noticed insects feeding on flower nectar. As they do so, pollen grains from the anther stick to their bodies. When the insect moves to the stigma of a similar flower, the pollen grains transfer to the stigma. This process is called pollination. Insects are the main agents of pollination, helping to carry pollen from one flower to another.
• The stigma produces a sweet nectar that attracts insects. When insects land to drink nectar, they transfer the pollen on their bodies to the stigma. Once the pollen reaches the stigma, it forms a pollen tube that grows through the style to the ovary. The contents of the tube combine with the ovules, forming seeds.
• As this happens, the ovary swells and turns into a fruit, encasing the seeds inside. If the stigma does not receive pollen, the flower cannot reproduce, and will wither and die.
This process helps plants reproduce, continue their life cycle and maintain balance in nature.
Pause and Answer
Answer the following in one word.
1. It is the green leaf-like structure of a flower.
2. It is the colourful part of the flower that attracts insects.
3. It is the male part of the flower.
4. It is the female part of the flower.
encasing: as to cover or to enclose
Formation of seeds
Pollen Grain
Stamen Anther Filament Petal
Ovary
Seedling Seed
Ovule
Stigma Pollen Tubes Style Sepal
Growing Plants from Seeds
Let us understand the structure of a seed and how it grows into a full-grown plant.
Structure of a Seed
Seeds are found inside the fruit. The size, shape and structure of seeds of different plants vary considerably, but the basic structure of most the seeds is similar. A seed has three main parts—the seed coat, cotyledons (or seed leaves) and the embryo (or baby plant).
Seed Coat: The external covering of a seed is called the seed coat. It protects the baby plant that lies inside the seed.
Cotyledons or Seed Leaves: These store food for the growing embryo. Until the plant grows its own green leaves, it uses the food stored in the cotyledons to grow.
Embryo or Baby Plant: It is the baby plant that will turn into a seedling or a young plant.
Germination of Seed
Germination is the process by which a seed begins to grow into a seedling. For a seed to sprout, it needs to be planted in the right soil and provided with water, air and warmth. However, not all seeds turn into plants, as some are destroyed by rain, wind, insects, or birds, while others don’t get the right conditions to grow. The process of germination follows several stages:
• The seed is planted in soil and regularly watered while receiving air and warmth.
Did You Know?
The Giant Sequoia Tree produces seeds that are so tiny they can weigh less than a grain of sand. Despite their small size, these seeds can grow into some of the largest trees on earth.
Stages of seed germination
• It absorbs water, causing the seed coat to break open.
Seed coat
Parts of a seed
Cotyledon
Baby plant Shoot
• Once the seed coat breaks, a seedling emerges while drawing nutrients from the cotyledons initially before taking them from the soil.
• Tiny roots begin to grow along with a shoot.
• The seedling develops leaves and branches, eventually growing into a full plant.
Error Alert!
Be careful not to overwater your seeds when you plant them. Too much water can prevent air from reaching the seeds, stopping their growth.
Dispersal of Seed
Some seeds grow very close to each other and their parent plant, leading to competition for water, nutrients, light and space. This means that only a few seeds may survive while others perish. To improve their chances of survival, plants use various agents such as explosion, wind, water and animals to spread their seeds away from the parent plant. The process of scattering seeds away from the parent plant is known as seed dispersal. The following are some of the natural ways of seed dispersal:
• Dispersal by Wind: Seeds that are dispersed by the wind are small and light. Some examples include cotton and dandelion seeds which have tufts of hair, while maple seeds have wings to help them float in the air. Some other examples include drumstick and teak.
• Dispersal by Water: Plants near water disperse seeds and fruits through water. The examples include coconut seeds which have a fibrous covering that helps them float and lotus seeds which are found in spongy fruit that floats on water.
• Dispersal by Animals: Animals, birds and humans eat fleshy fruits like mangoes and discard the seeds, which can grow into new plants. Some seeds have hooks, spines or hairs that stick to animal fur or feathers and are carried to new places; examples include xanthium, tiger nail and spear grass.
• Dispersal by Explosion: Some plants like poppy, peas and beans have fruits that burst open when they are ripe and scatter seeds in all directions. This method of dispersal is called explosion.
perish: to die
Dandelion seed
Floating coconut
Xanthium seeds
Explosion of pea seeds
Pause and Answer
Write True or False.
1. The seed coat is the internal covering of a seed.
2. Cotyledons store food for the growing embryo.
3. Seeds will germinate if it is too cold.
4. Mango seeds are dispersed by wind.
5. Animals do not play any role in seed dispersal.
Growing Plants from Roots
Some plants can grow from their roots, without needing the seeds. For example, sweet potatoes, carrots, radishes, turnips and dahlias.
Investigate and Discover
Aim: To observe and understand how a new plant can grow from the top of a carrot. Materials Needed: A fresh carrot with its top (about 2–3 cm), a small shallow dish or bowl, water, cotton balls or a small piece of sponge and a space for enough sunlight
Method:
Step 1: Take a fresh carrot and cut off the root part, leaving about 2–3 cm of the carrot attached to the green leafy top.
Step 2: Place a few cotton balls or a small piece of sponge in the shallow dish or bowl. Place the carrot top on the cotton balls or sponge, with the cut side facing down.
Step 3: Pour a small amount of water into the dish, enough to keep the cotton balls wet.
Step 4: Put the dish near a window where it can get plenty of sunlight.
Findings: Over the next few days, observe the carrot top for signs of new growth. The green leafy top should begin to grow taller, and small roots may start to develop at the bottom.
Conclusion: Some plants, like carrots, can grow from their roots.
Growing Plants from Stems
Plants like potatoes, ginger and onions have underground stems. These stems have many buds that can grow into new plants when conditions are right.
The buds on a potato are called eyes. If you plant a piece of potato with an eye in moist soil, it will grow into a new plant in a few days. Plants such as lilies, tulips and chrysanthemums grow from underground stems called bulbs.
Some plants can be grown from stem cuttings. For example, rose, sugarcane and money plant can grow from a piece of the plant’s stem.
Do and Learn
Growing a rose plant from stem cutting.
• Choose a healthy rose stem about 6–8 inches long. Cut it just below a leaf node and remove the lower leaves.
• Plant the cut end in a pot with moist soil.
• Place the pot in a bright spot (but not in direct sunlight) and keep the soil moist. After a few weeks, new leaves should appear, indicating the cutting has rooted and is growing.
Growing Plants from Leaves
Some plants have special leaves that develop buds along their edges. These leaves are thick and fleshy. For example, Bryophyllum and Begonia. In these plants, the buds along the leaf edges can grow into new plants.
A bud growing from a potato stem.
Growing a rose plant from stem cutting.
Bryophyllum leaf
Pause and Answer
Identify the part of the plant through which the following plants can reproduce.
Agriculture
Plants provide us with food, oxygen, medicine, timber and many other resources. We cultivate plants extensively to meet our needs. This large-scale cultivation of plants for food products and other uses is known as agriculture.
Crops
The plants that are cultivated in large amounts in a specific area are referred to as crops. There are different types of crops:
• Food Crops: These are grown for human consumption, such as rice, wheat and vegetables.
• Cash Crops: These are grown to sell, like cotton and coffee.
• Feed Crops: These are grown to feed animals, like corn and hay.
To grow healthy crops, farmers needs to work hard and take care of the plants throughout the year. Here are the steps to grow healthy crops:
Ploughing: The soil is turned and loosened to prepare it for planting seeds. The loose soil allows air and water to pass through.
Sowing: In this process, seeds are carefully planted in the soil.
extensively: in a large scale or quantity
Cotton crop
Bryophyllum Ginger Rose
Ploughing
Sowing
Irrigation
Watering (Irrigation): Regular and measured watering of plants.
Adding Manure and Fertilisers: Crops need nutrients from the soil. Manures enrich the soil by adding humus, while fertilisers give specific nutrients to help plants grow strong.
Weeding
Adding manures and fertilisers
Weeding: Farmers remove unwanted plants, called weeds, from the field so they do not take the water and nutrients meant for the main crops.
Protecting Crops: Crops need protection from birds, insects, rats and pests. Farmers use scarecrows to keep birds away and spray pesticides to protect crops from insects and animals.
Harvesting
Protecting crops
Harvesting: When the crops are fully grown, farmers cut and collect them.
Storage: After harvesting, crops are safely stored to keep them fresh until they are used or sold.
manures: the waste matter from animals that is mixed with soil to make plants grow better fertiliser: a substance added to the soil to provide specific nutrients to the plants nutrients: substances that are needed to keep a living thing alive and to help it grow
Storage
Wonders of Bharat
India is the world’s largest producer of pulses and jute, and ranks as the second largest producer of rice, wheat, sugarcane, groundnut, vegetables, fruit and cotton.
Word Splash
pollination: the transfer of pollen from the male part to the female part in flowers embryo: the baby plant inside a seed germination: the process by which a seed grows into a new plant seed coat: the outer covering of a seed that protects it cotyledons (seed leaves): parts of a seed that store food for the baby plant dispersal: the process by which seeds are spread to new areas agriculture: the practice of growing plants on a large scale for food and other uses crops: plants grown in large quantities by farmers humus: decomposed plant and animal matter in the soil pesticides: chemical substances that are meant to kill insects that destroy crops harvesting: the process of gathering mature crops from the fields
Explore More!
Scan the QR code to learn more about reproduction in plants.
Points to Remember
• Plants are living organisms that breathe, grow, produce food and reproduce.
• Flowers attract insects for pollination and form seeds for new plants.
• Plants reproduce through the process of pollination.
• Seeds need water, air and the right temperature to germinate into new plants.
• Seeds disperse through wind, water, animals or explosions to avoid overcrowding.
• Plants can also grow from roots, stems or leaves besides seeds.
• Farmers grow crops on a large scale to provide food and other materials.
Chapter Checkup
1. Tick ( ) the correct option.
A. What is the primary function of petals in a flower?
Protect the flower Store food Attract insects Disperse seeds
B. Which part of the seed stores food for the growing embryo?
Seed coat Cotyledons Embryo Root
C. The baby plant inside a seed is called the:
Seed coat Cotyledons Embryo Ovary
D. What do seeds need to germinate?
Light, soil and fertiliser
Only water and soil
Water, air and suitable temperature
Only sunlight
E. Seeds dispersed by animals often have: Wings Hooks or spines
Fibres to float in water The ability to explode out from the shell
F. Which of the following plants can grow from roots?
Rose Potato Carrot Mango
2. Fill in the blanks.
A. The external covering of a seed is called the .
B. The of a flower develops into a fruit.
C. store food for the growing embryo.
D. of some plants like sweet potatoes can grow into new plants.
E. Manures and fertilisers provide to crops.
3. Write True or False.
A. Sepals are usually brightly coloured.
B. Insects are main agents of pollination.
C. Seeds need both air and water to germinate.
D. Plants can grow from stem cuttings too.
E. Watering is necessary for crops to grow.
4. Short-answer questions.
A. Describe the process of pollination.
B. What conditions are necessary for seed germination?
C. What is the significance of seed dispersal?
D. How do seeds dispersed by water adapt to their environment?
E. How can a new plant grow from a stem cutting?
F. Why do farmers use fertilisers?
5. Long-answer questions.
A. Describe the structure of a seed and its parts.
B. Discuss the importance of seed dispersal and the different methods by which seeds are dispersed.
C. What are the main steps involved in agriculture? Write one line about each.
D. With the help of a labelled diagram, explain the structure of a flower.
6. Picture-based questions.
A. What do you think the bee is doing in the picture?
B. What is this process called?
C. What is the result of this process?
Challenge (HOTS)
1. How would the absence of insects affect the reproduction of flowering plants?
2. What are the advantages of growing plants from roots instead of seeds? Provide examples of plants that can be grown this way.
Life Skills
Crops are important for our food supply, and farmers work very hard to cultivate them. They plant seeds, water the plants, and care of them until they are ready to be harvested. You can help your family and friends understand a farmer’s hard work, and the importance of not wasting food. Also, encourage your family to buy local and seasonal fruit and vegetables.
INTEGRATED
7 Animal World
Chapter Overview
Habitat of Animals
Animal World
Feeding Habits of Animals
Adaptations in Animals Migration in Animals
Get Set
Help the animals find their homes.
Like us, animals also need food and shelter to survive. But how do animals survive against heat or cold? And how do different animals live in different places? We will find answers to these questions in this chapter.
Habitat of Animals
The natural home of animals is called their habitat. Habitats provide food, water, shelter to animals. Several kinds of plants and animals live in the same habitat. For example, the ocean is a habitat because it is a natural home for various aquatic plants and fish.
Only the natural home of an animal can be called a habitat. For example, a zoo is not the habitat of a tiger because it is not its natural home.
There are different types of habitats such as forests, deserts, the polar regions, freshwater bodies (rivers, lakes and ponds), and oceans. Let us learn about them.
Forests
A forest is a large area covered with trees. They are important because they are home to many animals, they clean the air we breathe and offer us resources such as wood and paper.
Some animals that live in forests are elephants, tigers, leopards, baboons, foxes, wolves, snakes and bats. Many kinds of birds, like eagles, owls, kingfisher and mynas and peacocks live in forests.
Deserts
A desert is an extremely dry area as it receives very little rainfall. Animals such as camels, scorpions, desert snakes and hedgehogs are found in deserts. These animals have thick skin to reduce water loss through sweating. Some find shelter in burrows to escape the heat, while others store water and food in their bodies. These adaptations enable them to survive in the harsh, water-scarce environment of the desert.
Did You Know?
An area in a desert where water and plants can be found is called an oasis.
shelter: a place that protects from weather or danger resources: anything available in our environment that can be used to fulfil our needs
Forest Camels in a desert
Polar Regions
Polar regions refer to the areas near the north (Arctic) and south (Antarctica) poles of the Earth. These high-altitude regions are covered with ice and snow all year round. In the Southern Hemisphere, you can find animals like penguins, whales and seals, while the Northern Hemisphere is home to polar bears, Arctic foxes and Arctic hares. These animals have thick fur and a layer of fat underneath their skin to stay them warm.
Freshwater Habitats
A freshwater habitat is a naturally-occurring water body on the Earth’s surface. There, the water is not salty. Rivers, lakes, ponds and streams are some examples of freshwater habitats. Many animals live in freshwater. Some of these animals include catfish, trout, frogs, turtles, water snakes, ducks, kingfishers and swans.
Oceans and Seas
An ocean is a huge body of saltwater that covers most of the Earth’s surface. Many animals live in oceans. Oceans are the largest habitats on Earth. Some of the animals found here are crabs, octopuses, whales, jellyfish, turtles, eels, angelfish, sharks and dolphins.
Pause and Answer
Name the following habitats.
1. A large area covered with trees.
2. A huge body of salty water that covers most of the Earth’s surface.
3. An area that remains covered with ice for most of the year.
4. A very dry place where hardly any rain falls.
Penguins in Antarctica
A swan in a lake
Jellyfish in the sea
Feeding Habits of Animals
We all know that our body needs energy to be alive, to grow and to perform various activities. We get this energy from the food we eat. If we do not eat food, we become weak and tired. We can even fall sick. Just like us, all animals also get energy from the food they eat. Animals can be grouped by what they eat. Some animals eat only plants, some eat only other animals and some eat both. This shows how different animals have different dietary habits.
Herbivores
Herbivores are animals that eat only plants. Their food includes leaves, grass, flowers, fruits, seeds and roots. They have a dental pad on the upper jaw and sharp front teeth, called incisors, on the lower jaw for biting. Their broad back teeth—molars and premolars, help them grind and chew their food. Some examples of herbivorous animals are deer, zebras, cows, sheep, horses, rabbits, elephants and giraffes.
We have learnt that herbivores eat plants and grass. They must grind their food into a paste before swallowing it, which requires strong, flat teeth. Have you ever seen how cows chew on grass? A cow’s mouth moves up and down to bite and from side to side to grind food easily.
Carnivores
Carnivores are animals that hunt and eat other animals. Some examples of carnivorous animals are foxes, wolves, lions, sharks, tigers, crocodiles, eagles, cats, frogs and snakes.
Carnivores have sharp canine teeth to tear meat, and strong molars to crush bones. Birds of prey such as eagles, have sharp, hooked beaks for tearing flesh. grind: to press and break something into very small pieces
Omnivores
Omnivores are animals that eat both plants and animals. Some examples of omnivorous animals are human beings, mice, bears, pigs and hens.
Omnivores have flat teeth at the back for grinding food and sharp teeth at the front for tearing it.
Scavengers feed on the flesh of animals that are already dead. They have sharp beaks or teeth to tear flesh. Examples of scavengers include vultures, jackals and hyenas.
Lice, ticks and fleas are parasites. They live on the body of another living being, and suck their blood for their food.
Pause and Answer
Match the following.
Column I Column II
A. Omnivores i. Sharp teeth
B. Carnivores ii. Flat and sharp teeth
C. Herbivores iii. Strong and flat teeth
Adaptations in Animals
A fish can live in water but a camel cannot. The features of a fish help it to live inside water, however, the features of a camel are best suited for survival in a desert. These features that plants and animals develop to survive in their natural habitats, such as seas and deserts, are called adaptations.
The different ways in which plants and animals adapt to their habitats include:
• Body Covering
• Breathing Organs
• Organs for Movement
Body Covering
One way animals adapt is through their body covering, which can include fur, feathers, scales, shells or skin. These coverings help animals stay safe, find food, and survive in different climates.
Fur: Polar bears have thick fur to keep them warm in the icy polar regions. Their fur is also water-resistant, helping them stay dry after swimming.
Feathers: Birds have feathers that help them fly, stay warm, and sometimes even help them blend into their surroundings. Penguins have waterproof feathers to keep them dry while swimming.
Scales: Fish have scales that protect their bodies and help them swim smoothly.
Shells: Turtles and snails have hard shells on their back that protect them from predators and harsh environmental conditions. They can pull their heads, legs and tails into their shells for safety.
Did You Know?
A camel’s thick skin helps protect it from the hot sun in the desert. Camels can also close their nostrils to keep out the sand during sandstorms.
Breathing Organs
Animals live in different places, like water, land and air. They have special adaptations for breathing in each of these places. Let us learn how different animals have adapted their breathing organs to survive.
Gills
Animals such as fish, crabs and prawns breathe using gills. Gills are feather-like organs located in pouches on either side of the animal’s head that absorb oxygen from water.
water-resistant: to not allow water to pass through easily predator: an animal that kills and eats other animals
Gills
Lungs
Reptiles, birds and mammals breathe using lungs. Humans are also mammals. Air enters through the nose and travels down the windpipe to the lungs where gas exchange occurs between air and blood.
Spiracles
Insects breathe through tiny openings on their bodies called spiracles. These spiracles lead to a network of tubes known as trachea that extends to every part of their body, allowing air to enter through this network.
Error Alert!
Whales and dolphins have lungs too, but they don’t have a nose. They come to the surface to breathe air through blowholes.
Organs for Movement
Did You Know?
Fish have fins that help them swim smoothly through water. They have streamlined bodies that allow them to swim quickly and easily. Some animals, like frogs and ducks, have webbed feet for swimming in water.
streamlined: a shape that is narrow at the front and broad at the back
Animals such as frogs and toads are called amphibians. They can live both on land and in water. Young amphibians use gills to breathe in water, but adults depend on lungs and moist skin when on land.
Animals move from one place to another in search of food, shelter or safety from predators or natural disasters. This ability to move is known as locomotion. Different animals use different body parts for movement.
Birds have wings that help them to fly. Their wings are strong and covered with feathers which help them lift off the ground and glide through the air. Birds have light, hollow bones that make it easier for them to fly.
Fins
Animals such as deer and horses have strong legs that help them run fast to escape from predators. Their legs have muscles that give them the power to run and jump.
Do and Learn
Snakes do not have legs. Instead, they use their muscles to slither smoothly across the ground.
Choose an animal you find interesting and research more about it on the internet. Create a poster with pictures along with facts about its habitat, diet, behaviour, etc.
Pause and Answer
Give one word for the following.
1. The features that help plants and animals survive in their natural habitats.
2. The body covering that keeps polar bears warm in icy polar regions.
3. The breathing organs in fish that absorb oxygen from water.
4. The body part that helps fish swim smoothly through water.
5. The tiny holes in insects’ bodies used for breathing.
Migration in Animals
Migration is the regular movement of animals from one area to another, caused mainly due to unfavourable weather conditions, the search for new habitats, or food shortages. This movement occurs at specific times and during certain seasons. Animals may also migrate due to natural disasters such as earthquakes, droughts and floods. Some species travel to specific areas at specific times of the year to give birth to their young ones; these locations are known as breeding grounds.
slither: to move by sliding from side to side along the ground
Certain birds, known as migratory birds, migrate twice a year during spring and autumn. They do this to avoid harsh weather and to find food. For instance, the Arctic tern breeds near the north pole in summer and migrates all the way to Antarctica in autumn to escape extreme cold.
Discuss!
What could happen to a bird if it did not migrate when its food sources became scarce? Discuss with your classmates.
Other animals, like caribou, elk and whales, also migrate in search of food. Certain insects, such as butterflies and moths, also migrate. The monarch butterfly, for instance, migrates from Canada to Mexico during winter.
Wonders of Bharat
Flamingos are known for their long migrations, and every year thousands of them travel to India. These beautiful birds fly from regions like Siberia and the Middle East to wetlands in Gujarat and Maharashtra. They come to India during the winter months, searching for food and a safe place to breed.
Word Splash
habitat: a natural home of an animal or a plant
adaptation: the features that plants and animals develop to live in a habitat
fur: the soft thick hair that covers the bodies of some animals
scale: a small rigid plate that grows out of the skin of a fish
shell: a hard covering that protects some animals
spiracles: a respiratory organ in insects
migration: the movement of animals from one place to another in search of food, better climate and shelter
Explore More!
Scan the QR code to learn more about habitats.
A caribou
Flamingos
Points to Remember
• The natural home of animals is called its habitat.
• Since animals eat different types of food, they can be classified based on the food they eat: herbivores, carnivores, omnivores, scavengers and parasites.
• The features that plants and animals develop to survive in their natural habitats are called adaptations.
• Animal migration is when animals move from one place to another at certain times of the year to find food, better weather or safe places to raise their young ones.
Chapter Checkup
1. Tick ( ) the correct option.
A. Which of the following is not an example of a habitat?
Desert Nest Forest Ocean
B. Which of the following animals have fins for movement?
Tiger Fish Frog Camel
C. Which organ helps animals breathe underwater?
Lungs Spiracles Gills Blowhole
D. Which animal has scales as its body covering?
Dog Butterfly Fish Duck
E. Why do some animals, like polar bears, have thick fur?
To look bigger To keep warm in cold climates
To help them swim To scare predators
2. Fill in the blanks.
A. The natural home of animals is called a .
B. Fish have that help them swim smoothly in water.
C. Polar regions are covered with for most part of the year.
D. are the habitats of camels.
3. Match the following.
A. Desert i. Elephants
B. Forest ii. Penguins
C. Ocean iii. Camels
D. Freshwater habitats iv. Whales
E. Polar regions v. Swans
4. Write True or False.
A. Deserts receive a lot of rainfall.
B. Both day and night are extremely hot in the deserts.
C. Soil remains frozen in the polar regions.
D. It is easier for us to breathe air under water than on land.
5. Short-answer questions.
A. What is a habitat?
B. Write a short note on the feeding habit of carnivores.
C. Provide an example of a living organism that has adapted to the following environments:
a. In polar regions b. In deserts c. In water
D. Define parasites, with examples.
E. Briefly explain the importance of shells in snails and turtles.
F. Give two differences between the teeth of carnivores and herbivores.
6. Long-answer questions.
A. Why do animals migrate? Explain with the help of three examples.
B. Explain the differences in the way fish and insects breathe.
C. How do the following features help a fish adapt to its habitat?
a. Shape
7. Picture-based questions.
b. Scales c. Fins
A. Identify the animal shown in the image and name its habitat.
B. How does its thick fur and layer of fat help it survive in the cold polar region?
C. What special adaptations does it have to walk on snow in this icy habitat?
Challenge (HOTS)
How do you think climate change might affect animals living in the Arctic circle and Antarctica?
Life Skills
Just like how adapt, we also need to learn how to handle changes around us. It could be starting a new school, making friends in a new place, or facing surprises like bad weather. Being able to adjust helps us become stronger. Write a diary entry about a challenge you faced and the ways you found to overcome it.
8 Environment and Pollution
Chapter Overview
Get Set
Let's play a fun game to understand our surroundings better.
Step 1: Take a paper chit. Write the name of something that you commonly see around you—it could be plants, animals, vehicles, a plastic bag or books.
Step 2: Make more such chits and put them into a bowl on the teacher's table. Mix them up.
Step 3: Now, one by one, pick a chit. Read what's written on it.
Step 4: Let others decide if that thing is good or bad for our surroundings. Also, discuss why.
Environment is everything that surrounds us. It includes living things like plants and animals, and non-living things like soil, air and water. A clean and healthy environment is important for the well-being of all living beings. However, human activities have increasingly harmed the environment, resulting in various form of pollution. Let us learn about pollution and its effects on our environment.
GAMES
What is Pollution?
Pollution occurs when harmful or poisonous substances are introduced into the environment. These substances can make air, water and land, unsafe for humans, animals, and plants. Such harmful substances are known as pollutants. There are four major types of pollution—air pollution, water pollution, land pollution and noise pollution. Let us learn about each of them in detail.
Air Pollution
Imagine you are travelling by bus or car, and you see a truck in front of you releasing a thick black smoke. That black smoke is an example of pollutant, making the air dirty and hard to breathe. Air pollution occurs when harmful substances like gases, dust, or smoke enter the air and affect the quality of air we breathe. Some causes of air pollution are:
• Burning fossil fuels (like, coal and petroleum) and garbage releases toxic gases such as carbon monoxide, carbon dioxide and methane into the air. These gases are very harmful and can cause respiratory diseases like asthma and lung cancer.
• Natural activities like volcanic eruption and forest fires release ash and gases into the air and pollute it.
• Spraying pesticides and fertilisers can also lead to air pollution.
Did You Know?
Gases like carbon dioxide and methane trap the Sun’s heat, raising the temperature of the Earth. This phenomenon is known as the greenhouse effect and these gases are called greenhouse gases. This increase in Earth’s temperature due to this effect is called global warming.
toxic: containing poison respiratory: related to breathing
Think and Tell
Mention two ways in which you can help reduce air pollution.
Do and Learn
Let us see the effects of air pollution. Take two identical plastic bottles and fill them with cotton balls. Cover one bottle with a thin layer of cloth and leave the other bottle uncovered. Place the bottles outside for a day. Position one bottle in a busy area (like near a road) and the other bottle in a less polluted area (like in a garden). At the end of the day, compare the cotton balls in both bottles to see how much dust and pollutants were collected. Discuss how air pollution affects our lungs similarly.
Water Pollution
Imagine visiting a beach and finding it littered with plastic or seeing a river filled with garbage—this is the result of water pollution. It affects not only the animals living in the water but also the water we drink and use every day.
The addition of harmful substances in water bodies like rivers, lakes, seas and oceans causes water pollution. This makes the water dirty and unsafe. Water pollution can occur in various ways:
• Throwing household garbage, plastics and untreated industrial wastes into water makes it dirty and unfit for use. Consuming dirty water can cause diseases like jaundice, typhoid, cholera and dysentery.
• Human activities, such as washing clothes and bathing in water bodies, cause water pollution.
• Pesticides and fertilisers get mixed with rain and enter water bodies, thereby polluting them.
• Oil spills from ships cover the surface of oceans and seas. Due to this, aquatic life finds it difficult to breathe and survive.
Investigate and Discover
waste discharged into water
Aim: To study the effects of different pollutants on water.
Materials Needed: clear plastic containers, clean water, various pollutants (soil, oil, food colouring, small pieces of plastic, paper scraps), a spoon, small nets, cotton balls or coffee filters
Method:
Step 1: Fill the clear plastic container with clean water. This represents a clean water source.
Untreated
Oil spill
Step 2: Ask students to take turns one by one and add different pollutants to the water (soil to represent dirt runoff, oil to represent oil spills, food colouring to represent chemical pollutants, and small pieces of plastic and paper to represent litter).
Step 3: Stir the water gently with a spoon to mix the pollutants.
Step 4: Observe the water and note changes in its appearance, colour and clarity. Discuss how each pollutant affects water.
Findings: Larger pollutants are easier to remove from water with the help of nets. However, smaller and finer particles are difficult to remove from water.
Conclusion: Any kind of impurity (small or large) is harmful to water. These pollutants contaminate water and make it unsafe for consumption.
It is a common mistake to think that polluted water is always dirty or smelly. Sometimes, water can look clear and still be polluted with harmful chemicals or germs that you cannot see.
Land Pollution
Imagine you are walking in a beautiful park, but you see trash everywhere—plastic bottles, candy wrappers and old newspapers. How would you feel? You will not feel good at all. All this litter contributes to land pollution. Let us learn more about it.
When harmful substances are added to the soil or land, making it dirty, unhealthy or unsafe, it is called land pollution. It can happen in various ways:
1. Throwing solid wastes, such as plastic bags, metal containers, and glass bottles on the ground can pollute the soil and harm wildlife.
2. The roots of trees hold the soil in place. Deforestation causes strong winds and rain to wash away the top layer of the soil, causing soil erosion.
3. Extracting minerals from the earth can cause the land to become polluted and degraded.
Remember!
Clean air, water and land are the basic requirements for life to flourish.
Land pollution
Noise Pollution
Imagine you are trying to read your favourite book, but there is loud music playing, dogs barking and cars honking outside. Will you be able to focus? All these loud sounds together can be very annoying and even harmful. This is called noise pollution.
When loud noises are produced by the honking of vehicles, loudspeakers and construction sites, it causes noise pollution. If we hear these loud noises for a long period, it may lead to deafness. Noise pollution can cause stress, hearing loss, sleep disturbances, and other health issues. Loud noises can disturb animals, affecting their behaviour and habitat.
Pause and Answer
Choose the odd one out.
Use of loudspeakers
Noise produced from construction sites
1. Burning of fuels Air pollution Dysentery Smoke
2. Carbon dioxide Methane Oxygen Greenhouse gases
3. Noise pollution Deafness Loud speakers Water pollution
Ways of Reducing Pollution
1. Factories should be located away from the residential areas. They should have filters so that the harmful gases and smoke are processed and not released out in the air.
2. We should plant more and more trees in our surroundings.
Discuss!
Are there any rules or guidelines that could help keep noise levels down in public places? Discuss with your classmates.
3. Different types of waste should be treated before getting dumped.
4. We should avoid using plastic bags and bottles.
Plant trees in your surroundings.
deafness: unable to hear
5. We should use natural fertilisers for agricultural purposes.
6. The government should ban unnecessary honking of horns on the roads.
7. We should adopt the formula of the 3R’s (reduce, reuse and recycle) to prevent pollution.
Wonders of
Due to the actions taken by the Namami Gange river conservation plan, around 4,000 Indian river dolphins have returned to the Ganga and its tributaries. This shows that the rivers are slightly cleaner than before, and it has encouraged the people and the government to put in more effort to prevent river pollution in India.
environment: all living and non-living things in our surroundings pollutants: the harmful substances that cause pollution
air pollution: the addition of harmful particles in the atmosphere
water pollution: the addition of harmful chemicals, waste and plastic in water bodies
land pollution: polluting of the soil due to garbage, plastic waste and deforestation
noise pollution: loud noise that affects the health of humans and animals
Word Splash Explore
The 3R’s
Bharat
Points to Remember
• All living and non-living things in our surroundings make the environment.
• Pollution is caused by the addition of harmful substances into the environment.
• There are four main types of pollution—air, water, land and noise.
• We should follow measures to reduce pollution and save our environment.
Chapter Checkup
1. Tick ( ) the correct option.
A. What is air pollution?
The contamination of water by harmful substances.
The contamination of soil by harmful substances.
The contamination of air by harmful substances.
The contamination of noise by harmful substances.
B. Which of the following is a major cause of water pollution?
Planting more trees. Using solar energy. Disposing industrial waste into rivers. Riding bicycles.
C. How can we reduce land pollution?
By throwing garbage everywhere. By burning plastic waste. By recycling and reusing materials. By cutting down trees.
D. What is noise pollution?
The presence of harmful chemicals in water.
The excessive and harmful levels of noise in the environment.
The presence of unwanted materials in the soil.
The increase in the earth’s temperature.
2. Fill in the blanks.
respiratory noise water global warming
A. Air pollution can cause problems like asthma and lung cancer.
B. The increase in the Earth’s temperature by greenhouse gases is called .
C. pollution can cause diseases like jaundice, typhoid and dysentery.
D. pollution is caused by the honking of vehicles, loudspeakers and construction sites.
3. Write True or False.
A. Throwing garbage into rivers and lakes causes water pollution.
B. Factories that burn coal and gas to produce energy release pollutants into the air.
C. Gases like carbon dioxide and methane are called greenhouse gases.
D. Noise pollution can cause stress and hearing loss.
4. Circle the correct alternative in each of the following.
A. Air / Water pollution occurs when harmful substances enter into air.
B. Water / Noise pollution makes water dirty and unsafe for use.
C. Land / Noise pollution can cause stress, hearing loss and sleep disturbances.
D. We should prefer to use natural / chemical fertilisers for agricultural purposes.
5. Short-answer questions.
A. Name two diseases caused by air pollution.
B. What is the greenhouse effect? Which gases are responsible for the greenhouse effect?
C. Mention ways to prevent water pollution.
D. How is land pollution caused?
E. Mention one harmful effect of noise pollution.
6. Long-answer questions.
A. Explain air pollution and factors causing air pollution. Mention its effects on environment as well.
B. How is noise pollution caused? What will happen if we are exposed to loud noises for a longer time period?
C. List some ways to prevent pollution.
7. Picture-based questions.
A. Which type of pollution is depicted in the given image?
B. What major cause of the pollution is being shown in the above image?
C. Write one harmful effect of the above-mentioned pollution on human health.
Challenge (HOTS)
If you were the governor of your city, what steps would you take to ensure that local water bodies, the land and the air are not polluted by the residents?
Life Skills
With the help of your neighbours, volunteer to clean one neighbourhood park. Sort the wastes into different types: all the recyclable wastes in one bag and the non-recyclables in another. Also try to plant grass and local plants and trees in the park.
Air and Water
Chapter Overview
Atmosphere Air Around Us Water in Nature Purifying Drinking Water
Get Set Air and Water
Look at the images and identify the thing (air/water) required for the activity. Write it in the box given below the images.
Atmosphere
A thick layer of air surrounds the Earth, known as the atmosphere. It is held around the Earth by gravity and is made up of gases like oxygen, nitrogen, carbon dioxide and others. The atmosphere is essential for life on Earth in the following ways:
1. Provides oxygen: The atmosphere contains oxygen, which all living beings need to breathe.
Drying of clothes
Birds flying
Washing clothes
2. Supports plant life: Plants absorb carbon dioxide from the atmosphere and use it to produce food through photosynthesis.
3. Protects from harmful rays: The atmosphere shields us from the sun’s harmful UV rays and helps regulate Earth’s temperature.
4. Blocks meteors: It acts as a protective barrier, preventing most meteors from reaching Earth’s surface.
Layers of the Atmosphere
Our atmosphere is divided into five layers—troposphere, stratosphere, mesosphere, thermosphere and exosphere. Let us learn about each of them.
1. Troposphere: Being the first and the innermost layer surrounding the Earth’s surface, it provides air for breathing. This layer contributes to the changes in the weather we experience.
2. Stratosphere: This is the second layer in the atmosphere. Aeroplanes fly in this layer to avoid any weather changes. This contains the ozone layer which protects the Earth’s surface from the harmful ultraviolet rays emitted by the Sun. These rays may cause skin cancer.
3. Mesosphere: This is the third layer of the Earth’s atmosphere. It protects the Earth by burning up meteors as they enter, preventing them from reaching the Earth’s surface.
Discuss!
There are other celestial bodies, like the planet Venus, that have an atmosphere. Do you think life is possible there? Discuss in your class.
4. Thermosphere: This is the fourth layer of our atmosphere. In this layer, the temperature can reach approximately up to 2000˚C. Space shuttles orbit around the Earth in the thermosphere.
5. Exosphere: This is the fifth and the outermost layer. There is no life beyond this layer, as air does not exist. Artificial satellites orbit around the Earth in this layer. This layer opens up to the outer space.
Layers of atmosphere
Name the following layers of the atmosphere.
1. It provides air for breathing.
2. It protects us from the harmful UV rays.
3. It allows artificial satellites orbit around the Earth.
4. It lets the space shuttles orbit around the Earth.
Air Around Us
Air is everywhere around us. We cannot touch or see it, but we can feel it. Air is very important as we need it for our survival. It is used by all living things. For example; plants, animals and human beings need air to breathe.
Composition of Air
Air is a mixture of different gases. Let us learn about them.
Nitrogen: Nitrogen constitutes 78% of the air. Nitrogen cannot be used directly by plants and animals. The bacteria present in the soil help to convert atmospheric nitrogen into its usable form, which can be used by plants. Plants also obtain nitrogen artificially from pesticides and fertilisers. When the animals feed on these plants, they also get the required amount of nitrogen.
Oxygen: It is one of the most crucial components of air. Oxygen constitutes 21% of the air. It is required mainly by living beings for breathing. It is also required for burning.
Think and Tell
All living beings need oxygen to survive. Where does such a large amount of oxygen come from?
Other gases: We know that oxygen and nitrogen together make up 99% of the air. The remaining 1% of air comprises carbon dioxide, argon, water vapour and other gases.
Plants require carbon dioxide to prepare their food during the process of photosynthesis. Argon, a colourless and odourless gas, is used to make light bulbs and fluorescent bulbs. When water gets evaporated from the Earth’s surface, it becomes water vapour. The presence of water vapour leads to changes in weather. The amount of water vapour present in the air is also known as humidity.
Air also consists of hydrogen, helium, ozone, smoke and dust particles in it. Helium is a light gas and it is used to fill balloons.
Investigate and Discover
Aim: To prove that oxygen is required for burning.
Materials Needed: A matchbox or lighter, 1 glass beaker, 2 candles and a table
Method:
Step 1: Under an adult’s supervision, light both the candles and place them upright on a table.
Step 2: Cover one candle with a glass beaker.
Step 3: Observe what happens to both the candles.
Step 4: The candle covered with the glass beaker stops burning after some time. The other one continues to burn.
Findings: When we cover the candle with a glass beaker, the oxygen supply stops. The other candle keeps on burning as oxygen is supplied continuously.
Conclusion: Oxygen is required for burning.
Did You Know?
Living things are not only found in soil and water but also in the air. Bioaerosols are small particles in the air that carry things like bacteria, viruses, pollen or fungi. They can be released from plants, animals and human activities, like coughing or sneezing. Bioaerosols can affect human health, leading to allergies or spreading diseases.
Properties of Air
Oxygen is required for burning.
Error Alert!
It is commonly believed that air is same everywhere. But that is not true. Air quality can vary, depending on location, altitude and pollution levels.
Air is colourless, tasteless and odourless, but it has several important properties.
Air occupies space: Air is matter, so it takes up space. When you blow air into a balloon, the balloon inflates because the air fills and occupies the space inside it. The same happens with things like footballs, tyres and cushions.
odourless: without any smell
Air has weight: An inflated object weighs more than when it is deflated. This demonstrates that air has weight.
Investigate and Discover
Aim: To prove that air occupies space and has mass.
Materials Needed: A deflated balloon and a straw
Method:
Step 1: Take a deflated balloon.
Step 2: Insert a straw in it.
Step 3: Blow into the straw until the balloon gets inflated.
Step 4: Hold the balloon and try to feel its mass compared to when it was deflated.
Findings: The balloon gets inflated and takes the desired shape. It becomes heavier once inflated.
Conclusion: This shows that air occupies space. The balloon also becomes heavy as compared to the deflated one. So, it also shows that air has mass.
Balloon is inflated after filling air into it.
Air exerts pressure: Since air has weight, it pushes against objects in all directions, creating air pressure. This pressure is essential for everyday activities like drinking water or juices with the help of a straw, filling ink in a fountain pen and drawing liquid medicine into a syringe. Let us learn about them by conducting some activities.
Investigate and Discover
Aim: To prove that air exerts pressure.
Materials Needed: A glass, a piece of cardboard and water
Method:
Step 1: Fill a glass completely with water.
Step 2: Place the piece of cardboard over the top of the glass, ensuring there are no air bubbles.
Step 3: Hold the cardboard in place and carefully turn the glass upside down.
inflated: to fill something with air; deflated: to make something smaller in size by letting the air out
Step 4: Slowly release your hand from the cardboard while holding the glass upside down.
Findings: The cardboard stays in place, and the water does not spill out.
Conclusion: This experiment demonstrates that air exerts pressure from below, pushing up against the cardboard and preventing the water from falling.
Water in Nature
About 71% of our Earth’s surface is covered with water. It is obtained from different sources like oceans, rivers, lakes, ponds and wells. Water from different sources evaporates and condenses to form clouds in the upper atmosphere. Clouds become heavier and precipitate. Rainwater goes back to water sources. This cycle is called water cycle. Rainwater acts as the main source of water on the Earth. Water is used for various purposes, such as bathing, washing, cooking and cleaning.
Impurities in Water
We know that water is a universal solvent. This mean it can dissolve a wide range of substances into it. Sometimes, unwanted or harmful substances dissolve in water, making it polluted and unfit for use. These substances are called impurities.
Types of Impurities
Soluble Impurities: These impurities completely dissolve in water. Once mixed with water, we cannot see these impurities with our naked eyes. Some examples of soluble impurities include sugar and salt.
Insoluble Impurities: Unlike, soluble impurities, they do not dissolve in water. They are visible with our naked eyes. They can either float on water or settle down at the bottom. Some examples of insoluble impurities include sand and mud.
Water cycle in nature
Air exerts pressure
Removing Impurities
We have learnt about different types of impurities. Depending on this, different methods are used to remove different types of impurities. Let us learn about them.
Removing Soluble Impurities
Evaporation: In this method, soluble impurities are removed from water by heating. Heating changes water into steam, leaving the impurities behind in the vessel.
Distillation: In this process, water is heated and distilled water is collected on condensation.
The steps used in the distillation process are as follows:
1. The impure water is poured into the round-bottom flask. It is then heated until it starts boiling.
2. On boiling, water changes into steam or water vapours.
3. The produced steam is then passed through the condenser and becomes cool. This changes steam back to water.
4. The pure and clean water is then collected in the receiving flask. This water is called distilled water.
Removing Insoluble Impurities
Distillation
Insoluble impurities are removed by methods like sedimentation and decantation.
Sedimentation and Decantation: These are used to separate impurities like mud and sand, which are heavier than water.
Let us learn how to separate sand from water.
1. Mix some sand in a glass of water.
2. Let it stand undisturbed for some time.
3. After some time, you will observe that sand settles down at the bottom of the beaker. This process is called sedimentation.
Sedimentation and decantation
4. In sedimentation, clean water appears on the top.
5. Now, slowly pour the obtained clean water in an empty beaker. This process is called decantation.
Discuss!
We know that 71% of the Earth is covered with water. Given this, what do you think causes the issue of water scarcity in many places? Discuss your thoughts with your classmates.
Pause and Answer
Tick ( ) the correct alternative in each of the following.
1. Substances that make water unfit for consumption are called impurities/solvents.
2. Soluble/insoluble impurities get completely dissolved in water.
3. Soluble/insoluble impurities can either float or settle down in water.
4. Sugar/sand dissolves in water.
5. Distillation/sedimentation is used to separate insoluble impurities from water.
Purifying Drinking Water
Remember!
We should use water wisely and judiciously.
Water which comes to our houses through pipes and taps is unfit for direct consumption. It consists of various impurities and germs. This makes us fall ill. We suffer from various waterborne diseases like cholera, jaundice and hepatitis after consuming such impure water. So, we need to purify water before consuming. Let us learn about these methods.
Boiling
The boiling temperature of water is 100 degree Celsius. Did You Know?
This is one of the oldest and easiest methods to purify water at home. Water needs to be boiled for 15–20 minutes when its temperature reaches 100 degrees Celsius. In this process, the germs are killed. Once the water cools down, it needs to be stored in clean vessels for consumption. These vessels need to be covered and stored in a clean and dry place. Water filters and
purifiers can be used at home to clean drinking water. Potassium permanganate is also used to treat drinking water as it disinfects and helps prevent diseases.
Before water is supplied to our homes through pipelines, it undergoes purification and filtration using three main methods:
Sedimentation: Water from sources like rivers and lakes is collected in large tanks and left undisturbed for several days. During this time, solid impurities settle at the bottom of the tank. Sunlight also helps kill many germs present in the water. Alum is added to improve the water quality.
Filtration: After sedimentation, the water is filtered through a clean sand bed to remove finer insoluble impurities.
Chlorination: Finally, the filtered water is disinfected with chlorine to kill any remaining germs. Chlorine tablets are readily available and can eliminate most harmful microorganisms in the water, making it safe for use. This treated water is then supplied to homes for domestic purposes.
Do and Learn
Let us make a water filter.
We need a plastic bottle, craft knife, cloth/old sock, sand, pebbles, container, water. Cut the plastic bottle (under an adult’s supervision) and place it in the inverted form over the other half of the bottle. Cover the mouth of the bottle with a cloth/old sock. Add sand and pebbles to the opening of the bottle. Now, slowly add water in it. The water will slowly flow through the opening and will be poured in the bottom part of the bottle.
Wonders of Bharat
India has always stood out in keeping its rivers clean and using innovative ways to preserve natural resources. For example, rainwater harvesting in India began from around 4,000 years ago.
Water filter
Word Splash
atmosphere: a thick layer of air surrounding the Earth
meteors: a small piece of rock in space
orbit: a fixed curved path in which the celestial bodies move bacteria: single-celled micro-organisms
pesticides: chemical substances that are used to kill pests
fertiliser: a natural or chemical substance that is put on land or soil to make plants grow better
solvent: a liquid that can dissolve another substance
polluted: the presence of unwanted substances
germs: microbes present in food, water or everywhere
Explore More!
Scan the QR code to learn more about the layers of the atmosphere.
Points to Remember
• The Earth is surrounded by a thick layer of air, known as the atmosphere.
• Our atmosphere consists of five different layers.
• Air is a mixture of gases.
• Water is an important part of our daily lives.
• Impurities can be soluble or insoluble.
• Water needs to be purified before consuming.
Chapter Checkup
1. Tick ( ) the correct option.
A. Which layer of atmosphere contributes to the changes in the weather we experience?
B. Which gas is required for burning?
C. Which gas has the highest composition in air?
Oxygen Argon Nitrogen Carbon dioxide
D. Which of the following methods is used to separate soluble properties from water?
Decantation Sedimentation Distillation Chlorination
2. Fill in the blanks.
100 thermosphere 21 sedimentation
A. Air consists of oxygen in it.
B. When we boil water, it reaches the temperature of degrees Celsius.
C. In method, the heavy impurities settle at the bottom of water.
D. Space shuttles orbit around the Earth in .
3. Write True or False.
A. Air is used by all living things for breathing.
B. There is no life beyond the exosphere.
C. Weather changes happen because of the presence of water vapours.
D. 71% of our Earth’s surface is filled with water.
4. Match the following.
A. Troposphere i. air for breathing
B. Mesosphere ii. airplanes
C. Exosphere iii. burn meteors
D. Stratosphere iv. space shuttles
E. Thermosphere v. artificial satellites
5. Short-answer questions.
A. How is atmosphere useful to us?
B. Name different layers of the atmosphere.
C. Mention the sources and uses of water.
D. What are soluble and insoluble impurities? Give one example of each.
6. Long-answer questions.
A. Prove that an inflated tyre is heavier than a deflated tyre.
B. Briefly explain the different layers of the atmosphere with the help of a diagram.
C. Draw the diagram to show the composition of air and explain it.
D. Explain different water purification methods.
7. Picture-based questions.
A. Identify the process shown in the image.
B. Briefly explain the process.
Challenge (HOTS)
Suggest two ways in which factories can manage their wastes without dumping them in water bodies or releasing them in the air.
Life Skills
Carry out a water conservation drive in your society. Gather all your friends and family members to help you. Check how much water is used by everyone in your community. You can ask your neighbours or look at water bills to get this information. Find out where water is being wasted. Think about how water can be recycled and used for different purposes.
Rocks and Minerals
Chapter Overview
Label the different layers of the earth in the image given below. Get Set
Rocks
We can find rocks everywhere on the Earth. Many of the materials used in construction come from rocks.
Rocks consist of minerals, which are naturally occurring substances within the Earth. The minerals present in rocks differ, giving rocks distinct characteristics in terms of size, shape, composition and formation. In this chapter, we will learn about the different types of rocks based on how they are formed.
Rocks and Minerals
Rocks
Types of Rocks Minerals Fossil Fuels
Types of Rocks
Different types of rocks are formed by different methods. Some rocks are formed due to natural agents, like wind and water, while others are formed from older rocks. Some rocks are even formed due to the cooling of hot lava. Depending on the method of their formation, rocks are grouped into three types:
1. Igneous rocks
2. Sedimentary rocks
3. Metamorphic rocks
Let us learn about each of them in detail.
Igneous Rocks
The word ‘igneous’ means ‘fire.’ Igneous rocks are formed by the cooling of hot molten rock called magma, which lies deep below the Earth’s surface. When a volcano erupts, the hot magma rises and flows onto the Earth’s surface. At this point, it is known as lava. When the lava cools and hardens, it turns into solid rock, which is called igneous rock. Some examples of igneous rocks include granite, pumice and obsidian.
Granite: A Useful Rock
Granite is a hard and tough rock that forms when magma slowly cools down below the Earth’s surface. Its colour ranges from grey to pink, depending on the quantity of feldspar minerals present in it. Granite is hard and tough, so it is widely used for constructing buildings, flooring tiles and countertops.
Pumice: The Light Rock
Pumice is a lightweight igneous rock that can float on water. It is formed from frothy lava that cools down quickly. When the lava cools, the gases that are trapped in the froth create small bubbles, making the rock porous. Pumice is commonly used as a scrubber to remove dead skin from feet, for creating decorative landscapes, and as a building material.
feldspar: a type of mineral froth: bubbles formed in a liquid porous: materials containing pores
A volcanic eruption
Magma
Lava
Granite
Pumice
Obsidian: The Shiny Rock
Obsidian is a smooth and shiny igneous rock formed by the rapid cooling of lava, which prevents the formation of crystal structures. It is usually black or dark in colour, although it can also appear in other colours, such as brown, green or even translucent variations. When obsidian is broken, it forms sharp edges, making it useful for making cutting tools. Its shiny texture also makes obsidian suitable for crafting jewellery and ornaments.
Sedimentary Rocks
We know that certain physical factors, such as wind, water and temperature change, causing rocks on mountains to break down into smaller pieces. These smaller pieces are called sediments. Sediments are carried by rivers and deposited in layers at different locations. Due to repeated deposition, the lower layers of sediments get compacted and cemented over time, hardening into sedimentary rocks. Sandstone, conglomerate, limestone and shale are some examples of sedimentary rocks. Let us learn about each of them.
Sandstone
Sandstone is a sedimentary rock composed of sand-sized particles that are firmly cemented together. It often contains a significant quantity of quartz, which contributes to its durability. Many of India's historical buildings, such as the Red Fort and Qutub Minar, are made of sandstone, showing its use in architecture.
Conglomerate Rock
Conglomerate is a rough and durable sedimentary rock formed when gravel, stones and pebbles are cemented together by sand and minerals. This process results in an uneven texture due to the different sizes and shapes of the embedded particles. Conglomerate rocks typically exhibit different colours, such as grey, brown and orange. They are commonly used in construction and can also be polished for use in jewellery.
durable: strong and long-lasting
Obsidian
Sandstone
Conglomerate
Limestone
Limestone is a sedimentary rock formed from the accumulation of shells, corals and the skeletal remains of tiny sea animals on the seabed. Over time, these materials become compacted and cemented together. Limestone is primarily composed of calcite, a mineral found in the shells of sea animals. It is commonly used in various applications, including the manufacturing of paints, whitewash and cement.
Shale
Shale is a soft sedimentary rock formed by the layering of mud and clay minerals. This rock is found in different shades of grey and sometimes in black, red, green and brown colours. This rock breaks into layers very easily. Shale is used to make cement, tiles and bricks.
Discuss!
Would our lives get affected if there were no rocks on the Earth? Why or why not? Discuss with your classmates.
Metamorphic Rocks
Did You Know?
Chalk is made of limestone. It becomes colourful when different colours are added to it.
Colourful chalks
The word ‘morph’ means ‘to change form’. When igneous, sedimentary or older metamorphic rocks are subjected to the heat and pressure of the Earth, these rocks undergo some physical and chemical changes. This results in the formation of metamorphic rocks. Let us learn about some metamorphic rocks.
Slate
Slate is formed from shale, a type of sedimentary rock. It is dark grey in colour. Like shale, slate also splits into flat layers. Slate is used to make bricks, cement, blackboards and slates.
Gneiss
Gneiss is formed from granite, a type of igneous rock. Due to the presence of different types of minerals in it, gneiss looks striped. It is used as building material.
accumulation: to collect or gather split: to divide into parts
Limestone
Shale
Slate
Gneiss
Marble
Marble is a hard rock formed from limestone, a sedimentary rock. It is usually white in colour. It can be polished and cut to make buildings and statues. Marble is also used for flooring and ornamental purposes.
Quartzite
Think and Tell
Can you think of a monument that is made up of marble?
Quartzite is a hard and weather-resistant rock made of sandstone, a sedimentary rock. Quartzite is generally found in white or grey colours. But it is also available in shades of red, pink, yellow and orange. Quartzite is used in ceramic and glass industries. It is also used to make jewellery and ornaments.
Do and Learn
Find pictures of different monuments that are made up of different types of rocks. Paste them in your scrapbook and mention the names of the rocks used. Make your scrapbook look attractive. Show it to your friends.
Pause and Answer
Fill in the blanks.
1. Igneous rocks are formed by the cooling of hot molten rock called .
2. is a lightweight igneous rock that can float on water due to its porous nature.
3. Sedimentary rocks are formed from the compaction and cementing of over time.
4. is a type of metamorphic rock that is commonly used to make blackboards and slates.
5. is a durable sedimentary rock often used in the construction of historical buildings like the Red Fort.
Minerals
Rocks are made up of chemical substances called minerals. Minerals are formed as a result of the natural processes occurring inside the Earth. These can be simple or complex.
Remember!
Minerals are inorganic in nature. This means that they are not of plant or animal origin. Iron, calcium and potassium are important minerals for all living beings.
Marble
Quartzite
Types of Minerals
Metallic Minerals
Minerals from which valuable metals can be extracted are referred to as metallic minerals, or ores. Examples of such metals include aluminium, iron, copper, gold, and silver. Aluminium, iron, and copper are commonly utilised in construction, the production of electrical appliances, utensils, coins, and train coaches. Precious and expensive metals like gold, silver, and platinum are primarily used to create jewellery.
Non-Metallic Minerals
Minerals that do not contain metals are known as non-metallic minerals. Examples include calcite, mica, and quartz. Coal and petroleum are significant non-metallic minerals derived from rocks deep within the Earth’s surface. These fossil fuels are formed from the remains of ancient plants and animals that have been buried over time.
Magnet
Substances that generally attract iron are called magnets. These can also attract things made up of cobalt and nickel. Magnets are either natural or man-made. Magnetite is the best example of natural magnet. Man-made magnets are generally made of iron, nickel and cobalt. These magnets come in various shapes and sizes. In all magnets, one end is called the North Pole (N) and the other is called the South Pole (S). Like or same poles of a magnet repel each other, while unlike or different poles attract each other.
Investigate and Discover
Aim: To check that magnets attract iron objects.
Materials Needed: A magnet of any shape, some iron nails and a white sheet of paper.
Method: Spread the iron nails on a white sheet of paper and move the magnet over it. Here, we are using a horse shoe-shaped magnet.
Findings: Iron nails stick to the poles of the magnet.
Conclusion: All magnets attract iron objects.
Gold, silver and copper
A bar magnet
Iron nail
Uses of Minerals
Minerals have great importance in our daily lives. Some of these are mentioned below:
1. Gypsum and calcite are used in making building materials, such as concrete and mortar.
2. Minerals, like diamond, emerald and ruby, are rare and expensive and are called gemstones. Such minerals are found in the form of crystals.
3. We obtain some useful metals, like iron and copper, from some minerals. Such minerals are called ores. The metals obtained from these ores are used in making electrical wires, utensils, coins and train coaches.
4. Nitrates and sulphates are used as fertilisers, which help the plants to grow better.
5. We need iron, calcium and sodium for healthy functioning of our bodies. We use rock salt in our food.
Pause and Answer
Give one example of each.
1. Mineral used to make concrete.
2. Mineral used to make electrical wires.
3. Mineral used to make building materials.
4. Mineral used to make ornaments.
5. Mineral that is important for healthy body functioning.
Fossil Fuels
Precious gemstones
Not all minerals are ores. Minerals that usually consist of a high concentration of metals are called ores. Error Alert!
Fossil fuels are the remains of dead plants and animals buried deep under the Earth’s surface millions of years ago. They are mostly found in sedimentary rocks because these rocks form at temperatures and pressures that do not destroy fossil remains. Coal and petroleum are non-metallic minerals obtained from rocks present inside the Earth.
Coal
Coal is a black-coloured fossil fuel formed from dead plants buried with great pressure under the Earth’s surface millions of years ago. It is a solid fuel and extracted from the
ground. The process used to extract coal is called coal mining. Coal is used to produce electricity, running steam engines, cooking and heating.
Petroleum
Petroleum was formed from the remains of sea plants and animals that perished millions of years ago. These organic remains settled on the ocean floor, where they were gradually covered by layers of sediment. Over time, these remains underwent transformation and became a dark liquid trapped in the pores of rocks, resulting in the formation of crude oil called petroleum. Various products, including LPG, petrol, diesel, kerosene, and lubricating oil, are derived from petroleum. These products, such as diesel, are commonly used as fuels for vehicles and are also utilised in the production of paints and varnishes.
Conservation of Fossil Fuels
Fossil fuels were formed millions of years ago and are not a renewable resource; they will eventually be depleted. Once the reserves of fossil fuels are exhausted, they will no longer be accessible to us. Additionally, the combustion of fossil fuels contributes to pollution. Therefore, it is essential to conserve fossil fuels and explore alternative energy sources such as solar energy, hydropower and wind energy. These alternatives are continuously available and do not contribute to pollution.
Wonders of Bharat
The Taj Mahal is a World Heritage Site located in Agra, Uttar Pradesh, India. It is made of white marble, which is a metamorphic rock. This marble is popular for its luminescent white colour.
Word Splash
lava: molten rock that flows onto the Earth’s surface due to volcanic eruption magma: molten rock found below the Earth’s surface sediments: smaller pieces of rocks formed by the breakdown of mountains magnets: substances that attract iron ores: minerals from which metals are extracted
extract: to take something out crude: anything that is present in its natural form luminescent: (here) seemingly glowing
Taj Mahal
Explore More!
Scan the QR code to learn more about rocks.
Points to Remember
• The outer surface of the Earth is made up of rocks.
• Rocks are of three types: igneous sedimentary, and metamorphic rocks.
• Rocks are made up of chemical substances called minerals.
• Coal and petroleum are fossil fuels that are obtained from rocks present inside the earth.
Chapter Checkup
1. Tick ( ) the correct option.
A. The hot molten rocks that lie deep below the Earth’s surface are called Lava Crater Magma Minerals
B. Metamorphic rocks are formed due to
Chemical changes
Physical changes
Heat and pressure deep inside the Earth
Flowing of lava on the earth’s surface
C. Which of these are used to make a magnet?
Iron and nickel Gold and iron
Gypsum and mica Cobalt and silver
D. A type of white rock that is made of calcite is called Marble Sandstone Limestone Chalk
2. Fill in the blanks.
A. rocks are formed by the cooling of magma.
B. Gneiss is an example of rock.
C. Limestone and shale are examples of rocks.
D. Calcite and quartz are examples of minerals.
3. Write True or False.
A. The colour of a rock depends on the quantity of minerals present in it.
B. Obsidian and graphite are examples of igneous rocks.
C. Pumice is a heavy rock that sinks very easily in the water.
D. Minerals, like diamond and ruby, are called gemstones.
4. Match the following.
A. Granite i. fossil fuel
B. Sandstone ii. igneous rock
C. Slate iii. metallic mineral
D. Coal iv. sedimentary rock
E. Bauxite v. metamorphic rock
F. Quartz vi. non-metallic mineral
5. Short-answer questions.
A. How many types of rocks are there? Name them with an example of each.
B. How is shale different from slate?
C. How are metallic minerals different from non-metallic minerals?
D. Mention some uses of petroleum.
6. Long-answer questions.
A. What are minerals? Mention two uses of metallic minerals.
B. How are sedimentary rocks formed? Mention the characteristics of any two sedimentary rocks.
C. How is coal formed? Mention its uses.
D. Why are fossil fuels considered non-renewable resources? Discuss the importance of finding alternative energy sources.
7. Picture-based questions.
A. What type of rock is shown in the given pictures?
Picture A:
Picture B:
B. How are the rocks shown in the above images different from each other?
C. Mention one use of each rock that you have mentioned above.
Challenge (HOTS)
If you have a pumice, granite and marble, which one do you think will not sink when put in a bucket full of water and why?
Life Skills
Ajay visited the Taj Mahal with his family. He noticed that people were littering around the entrance to the monument. People had also scratched their names on the gateway wall. He felt bad that people were disrespecting a historical monument in this way as it reflected poorly on India. So, he resolved to talk about preserving India's historical monuments to his class after his holidays. What measures would you implement to help preserve them?
Picture A Picture B
PROJECT 2
Layers of the Atmosphere
Objective: Students will create a model of the layers of the atmosphere to understand their structure, composition and significance.
Materials Needed: Chart paper, colours, scissors, glue or tape, markers, cotton balls, images of aeroplanes, satellites, meteors, etc. (can be cut from magazines or printed), and rulers
Step 1: Learn About the Layers of the Atmosphere
Study the five main layers of the atmosphere: Troposphere, Stratosphere, Mesosphere, Thermosphere and Exosphere. Use school textbooks or supervised online resources to learn key characteristics, such as the temperature, altitude and what can be found in each layer.
Step 2: Make a Base Model
Layers of atmosphere
Take a large sheet of chart paper. Use a ruler to measure and divide the chart paper into five horizontal sections, representing each layer of the atmosphere. Colour each section differently to distinguish between the layers (e.g., blue for the Troposphere, yellow for the Stratosphere, etc.) and label them.
Step 3: Design Your Atmosphere Model
Draw or cut out pictures of objects and phenomena that fit into each layer (like clouds, aeroplanes, meteors, satellites and the International Space Station). Use cotton balls to create clouds for the Troposphere and paste the pictures and cotton balls in the appropriate layers on your model.
Step 4: Present Your Atmosphere Model
Share your model with the class and explain the characteristics of each layer, the objects found there and their importance. Discuss how each layer plays a role in protecting the Earth and supporting life.
Project Output: You have created a layered model of the atmosphere, demonstrating its structure and function. Present your model to the class.
Final Outcome: This hands-on project will help you understand the layers of the atmosphere and their importance to life on Earth.
To be read aloud and explained in the mother tongue by the teacher, as needed.
Assessment 2
Read the article. Answer the questions given below.
Exploring the Journey of Rocks
In a small town near the Vindhya Mountains, students went on a field trip to learn about different types of rocks. Their teacher showed them granite, explaining, “This is an igneous rock, formed when lava cools and hardens. It is strong and used in buildings.”
By the riverbank, they found sandstone, a sedimentary rock made from layers of sand and clay pressed together over time. The teacher added, “Sandstone was used to build many forts and palaces in Rajasthan.”
Later, in a park, they saw a white marble fountain. “This fountain is made of marble, a metamorphic rock. It started as sandstone, but deep in the Earth, heat and pressure turned it into marble,” the teacher explained.
The trip helped students understand how different rocks form and how they are used in everyday life.
1. Which type of rock is formed from molten lava that cools and hardens?
A. Sandstone B. Marble C. Granite
2. Which of the following best describes how sedimentary rocks are formed?
A. They form from cooled molten lava that turns into solid rock.
B. They form from tiny pieces of sand, mud, and pebbles that get pressed together over time.
C. They form from rocks that change due to heat and pressure deep inside the Earth.
3. Why do you think heat and pressure deep inside the Earth can change sandstone into marble? Does it also affect other types of rocks in the same way? Explain your reasoning in three sentences.
4. If you were asked to build a monument, which type of rock—granite, sandstone or marble—would you choose and why? Consider the properties of each rock and how they are used in construction.
To be read aloud and explained in the mother tongue by the teacher, as needed.
Sandstone Marble Granite
11 Matter and Its States
Chapter Overview
Matter and Its States
Matter
States of Matter
Change in States of Matter
Changes in Matter
Solubility of Substances
Get Set
Look at the given pictures. Write ‘S’ for solids and ‘L’ for liquids.
Observe different things in your surroundings. You will see things of different shapes and sizes. For example, buildings, plants, animals, clouds and many other things. All these things occupy space. Anything that has mass and occupies space is called matter. Here, mass is the amount of material present in an object.
Stone
Wood Water Oil
Think and Tell
Matter is made up of small particles called molecules. Molecules are tiny particles that we cannot see with the naked eye. Molecules are made up of atoms. Therefore, atoms are building blocks of matter. For example, water is made up of a large number of water molecules. Each water molecule is further made up of 2 atoms of hydrogen and 1 atom of oxygen.
Name five things that you see in your classroom. Would you call them matter or not?
Atoms are the building blocks of matter.
States of Matter
Depending on the arrangement of their molecules, the matter is present in three states. These are solids, liquids and gases. To understand these three states, you should know that molecules of matter have some spaces between them and they move continuously.
Solids
Molecules of solids are very closely packed. The image given shows molecules of a solid present close to each other with almost no space between them. They cannot move around freely. So, solids have fixed shapes and sizes. These are hard and cannot be compressed. Ice, pencil, apple and trees are some examples of solids.
Arrangement of molecules in a solid.
Sponge is a solid. However, it can be compressed.
Liquids
Molecules of liquids are not very closely packed. They have some space between them. They can move around freely as compared to solids. So, liquids can flow easily.
naked: uncovered arrangement: packaging
Arrangement of molecules in a liquid.
Error Alert!
Liquids don’t have a fixed shape but they take the shape of the container in which they are poured in. Water, tea, milk and oil are some examples of liquids.
Gases
Molecules of gases are very loosely packed. The molecules of a gas have large spaces between them. They can move around freely and fill up the space of the container. So, gases don’t have a fixed shape and size. Air, oxygen and nitrogen are some examples of gases. Arrangement of molecules in a gas.
Pause and Answer
Tick ( ) the correct statements.
1. Nitrogen is an example of a liquid.
2. In gases, molecules are free to move in any direction.
3. Solids have a definite shape.
4. A liquid takes the shape of the container it is poured in.
Change in States of Matter
States of matter are interconvertible. It means that one state of matter can be changed into another. Matter can change from one state to another through heating and cooling. For instance, water turns into water vapour when heated, and ice becomes water when it melts. As this happens, the arrangement of molecules in the material also changes. Let us discuss how.
Evaporation: When you heat water, it turns into water vapour. Water vapour is water in its gaseous form. The process of changing water into gas by heating is called evaporation. When water gets hot, its molecules start to move faster. They break free from their previous arrangement and enter into the air as water vapour (gas).
Heating
Evaporation
Condensation: When the freely moving water vapours touch a cold surface, they cool down and form drops of liquid water. The process of changing a gas into its liquid form upon cooling down is called condensation. Cooling reduces the speed of the moving
interconvertible: changed into one another
particles. They become less free and enter the liquid state of matter.
Melting: Ice cubes are solid. They have a fixed shape and are rigid. When ice cubes are kept out of the refrigerator, they melt and form liquid water. The process of changing a solid into its liquid form is called melting. The outer space is warmer than the refrigerator. When placed in a warmer place, the particles of ice cubes move faster. They break down their rigid arrangement and become loosely packed to form liquid water.
Solidification: Water forms ice when it is kept in the freezer. The process of changing a liquid into its solid state upon cooling is called solidification.
So, we can say that heating makes the particles of matter move faster and take up more space. So, the size of matter increases on heating. This increase in the size of matter is called expansion. On the other hand, cooling slows down the movement of the particles. They occupy less space. So, the size of matter decreases upon cooling. This reduction in the size of matter is called contraction.
Changes in Matter
We all see many changes around us. Some examples of changes are the melting of ice cubes, cooking food, the growth of a plant, and the burning of paper. Changes are grouped into two types—physical and chemical changes. Let us learn about them.
Physical Change
A physical change is when a substance changes in its shape, size, or state without forming a new substance. These changes are usually temporary and reversible, like melting ice or folding paper. In a physical change, the material remains the same even though it looks different.
Let’s learn about some examples of physical changes.
Melting of Butter: When we take out butter from the refrigerator and leave it at room temperature, it starts melting. It solidifies when kept back in the refrigerator. There is no change in the taste of the melted butter and the solidified one. Here, the melting of butter does not make a new substance. Therefore, the melting of butter is a reversible change.
Melting of Butter
Inflating and Deflating a Balloon: When we blow up a balloon, it gets bigger (inflates). When we let the air out, it shrinks back to its original shape and size (deflates). This is a physical change because it can be reversed, and no new substance is formed.
Chemical Change
A chemical change is a type of change in which new substances are formed. It cannot be reversed and is a permanent change. Let us learn about some examples of chemical changes. Cooking Food (Making of an omelette): Take eggs, break them and pour the liquid content onto a hot pan. Once cooked, an omelette cannot be changed into an egg. This results in the formation of a completely new and different substance (here, an omelette). So, cooking an omelette from eggs is not a reversible change. A new substance, an omelette, is formed from raw eggs.
Burning of Wood: When we burn wood, it gets turns into ash. The ash cannot be converted into wood again. So, the burning of wood is a chemical change as it forms a new product and cannot be reversed.
Do and Learn
Choose a place in your garden at home or school. Ask an elder to get you a seedling. Plant the seedlings in the soil. Water it daily. Observe it daily and note down the changes in its size and shape. Repeat this for several days. Can you change the plant into the seedling again? Is the growth of the plant a physical or chemical change? Write down the observations in your notebook
Pause and Answer
Sort the following changes into physical or chemical changes. Fill in the table. burning of coal melting of wax rusting of an iron lock making chapatti from dough tearing of paper cooking of food boiling of egg boiling of water
Physical Changes Chemical Changes
reversible: something which can be changed to its previous form
Inflation and deflation of a baloon
Burning of wood
Making an omelette
Solubility of Substances
Richa wanted to make a glass of lemonade for herself. So, in a glass of water, she added squeezed in two halves of a lemon, added two teaspoons of sugar, and a pinch of salt. These things—the lemon juice, sugar and salt—dissolved in the water and a refreshing drink was ready. If we take lemonade as a solution, then sugar, salt and lemon juice are the solutes, and water is the solvent and the resulting drink is lemonade. Therefore, a solution is formed by mixing one or more solute with the solvent.
Remember!
A solute is a substance that gets dissolved. While a solvent is a substance in which a solute dissolves.
Solubility is the ability of a substance (solute) to dissolve in another substance (solvent) to make a uniform solution. Soluble substances are the solutes that completely dissolve in the solvent. The solutes that do not dissolve in the solvent are insoluble substances. Water can dissolve most of the substances in it. Therefore, it is called a universal solvent.
Types of Solution
Depending on the state of the solute and the solvent, the solution can be of various types.
1. Solids in Liquids: In this type of solution, the solute is solid and the solvent is a liquid, like water. For example, salt in water and sand in water. Here, salt is soluble in water, its molecules find space and fit between the water molecules. On the other hand, sand is insoluble in water and it settles down at the bottom of the container.
2. Liquids in Liquids: In this type of solution, the solute and the solvent are both liquids. The liquids that dissolve in water are miscible. Examples: Milk in water and ink in water. The liquids that do not dissolve in water are immiscible. They make a separate layer when mixed with water. Examples: oil in water, kerosene in water and petrol in water.
uniform: the same all over
Oil in water Ink in water
Salt in water
Sand in water
3. Gas in a Liquid: In this type of solution, the solute is a gas and the solvent is a liquid like water. Oxygen, carbon dioxide, nitrogen, and ammonia are some soluble gases (can dissolve) in water. Aquatic animals breathe in the oxygen dissolved in water. Carbonated drinks have carbon dioxide dissolved in water to make them fizzy.
Discuss!
What would happen if you left a bottle of carbonated drink open in the kitchen? Would its taste change or remain the same? Discuss with your classmates and answer.
On shaking and opening the bottle of carbonated drinks, carbon dioxide comes out as bubbles. This happens because the pressure at which the gas was dissolved in the water reduces upon opening the bottle.
Investigate and Discover
Aim: To check the solubility of various solids in water.
Materials Required: Salt, turmeric powder, coffee, chalk powder, sugar, wheat flour, a spoon, water, and some glass containers of the same shape and size
Method:
Step 1: Take different containers and arrange them on a table.
Step 2: Fill half of each container with water.
Step 3: Now add different solids in different containers. Make sure to add only one solid in one container.
Step 4: Once the solid is added, mix it properly with the help of a spoon.
Step 5: Wait for a few minutes and observe the changes. Record the observations in your notebook. Make a table as shown below.
Findings:
Solute added
Observations
1. Salt Dissolves well in the water.
2. Coffee
3. Chalk powder Settles down in the container.
4. Turmeric powder
5. Wheat flour
6. Sugar
Conclusion: Chalk powder, turmeric powder, wheat flour are insoluble in water. Salt, sugar and coffee are soluble in water.
fizzy: containing bubbles of gas
Wonders of Bharat
Gulmarg in Jammu and Kashmir is popularly known as the ‘Winter Wonderland’. It gets heavy snow fall every year. A lot of tourists visit this place for skiing in the winter season.
Word Splash
matter: anything that has mass and occupies space molecules: molecules are small particles that make up matter. atom: particles that make molecules, also known as the ‘building blocks of matter’ expansion: increase in the size of matter upon heating contraction: reduction in the size of matter upon cooling solubility: the ability of a solute to dissolve in a solvent to make a uniform solution soluble substances: the solutes that completely dissolve in the solvent insoluble substances: the solutes that do not dissolve in a solvent miscible: liquid solutes that can dissolve in liquid solvents immiscible: liquid solutes that cannot dissolve in liquid solvents
Explore More!
Scan the QR code to know more about the states of matter.
Points to Remember
• Anything that has mass and occupies space is called matter.
• Matter exists in three states—solid, liquid and gas.
• Different states of matter are interconvertible into each other by heating and cooling.
• There are two types of changes—physical and chemical changes.
• Solutions are formed by dissolving the solute in the solvent.
• The types of solutions depend on the states of solute and the solvent.
Gulmarg
Chapter Checkup
1. Tick ( ) the correct option.
A. Which of the following is not true about solids?
Definite shape
Definite size
B. Which of the following is a physical change?
Melting of ice cream
Digestion of food
C. Which of the following is a chemical change?
Boiling of an egg
Tearing of paper
D. Which of the following is miscible in water?
Oil
Kerosene
2. Fill in the blanks.
Rigid
Loosely arranged molecules
Burning of paper
Rusting of iron
Boiling of water
Cutting of wood
Milk
Petrol
A. The process of changing a liquid into its gaseous form on heating is called .
B. The process of changing a gas into its form upon cooling down is called condensation.
C. The process of changing a into its liquid form is called melting.
D. Water is a solvent.
E. Oil and kerosene are in water.
3. Write True or False.
A. Sand dissolves completely in water.
B. Salt settles down at the bottom of the container when mixed in water.
C. Evaporation is changing a liquid into its gaseous form on heating.
D. Changing a gas into its liquid form upon cooling down is called melting.
E. Physical changes are not reversible and form new substances.
4. Short-answer questions.
A. Why cannot we see molecules with the naked eye?
B. What happens when water is placed in the freezer for some hours? What is this process called?
C. What happens when sand is mixed with water?
D. Why do oil and kerosene form different layers in water?
E. Why are carbonated drinks fizzy?
5. Long-answer questions.
A. Differentiate between the three states of matter. Also, draw the diagram for the arrangement of molecules in solids, liquids, and gases.
B. Differentiate chemical and physical changes. Give two examples for each.
C. Define evaporation. How does it differ from melting?
D. Differentiate between soluble and insoluble substances. Give one example of each.
6. Picture-based questions.
A. What does the image show?
B. Why does the balloon inflate?
C. What happens when an inflated balloon is cooled down? Does it contract or expand?
Challenge (HOTS)
Aman left his bicycle outside in the rain for several days. When he checked, he saw that parts of the metal frame had rusted. Is this a physical or chemical change? Explain your answer.
Life Skills
Oil tankers and oil drills often have accidents that cause oil to spill into the ocean and pollute it. Take the help of the internet and/or an adult, teacher and find out:
• How do oil spills affect the fish living in the water?
• What can we do to reduce the use of oil so that there is less chance of oil spill?
• Mention one small step that you would follow to conserve water.
Oil spill
12 Force, Work and Energy
Chapter Overview
Force, Work and Energy
Force: Effects and Types Work Done
Energy: Forms and Resources
Look at the pictures and write if the force is a push or a pull. Also, in the boxes draw arrows to show the direction of the force. Get Set
Force: Effects and Types
Mia pushed the door of her room open and went to the kitchen. She then pulled out a chair to sit at the table. After breakfast, Mia went outside to play. She kicked the ball, rolling it across the ground. Mia’s morning was full of little actions that all involved force. Whether pushing, pulling or changing the direction of a moving object, she used force to do all of them.
Force is a push or pull that changes or tries to change the motion or position of an object. We use force in various activities. For example, pulling out a chair to sit on, pushing a shopping cart, a carpenter hammering nails into wood, or a person throwing a ball. In each case, an object moves because of the applied force, either pushing or pulling.
Though we can’t see force itself, we can observe its effect on objects. Let’s learn about the effects of force.
Effects of Force
Force can move a stationary object. It can stop a moving object or make an object move faster or slower. It can change the direction of a moving object. Force can also change the shape and size of an object.
Think and Tell
List two activities in which the shape and size of the object is changed by applying force.
its directions.
Pushing a toy car making it move across the floor.
Kicking a football can speed change
Squeezing a sponge changes its shape.
Hitting a ball with a bat can speed it up.
Effects of Force
Types of Forces
There are four main types of forces—muscular force, magnetic force, gravitational force and frictional force. Let’s learn about these types of forces.
Muscular Force
When we use our muscles to push or pull something; we apply muscular force. We can walk, run and jump due to muscular force. Animals such as bulls and horses also use muscular force to pull loads.
Magnetic Force
It is the force applied by magnets. Magnets attract magnetic materials like iron. For example, when iron nails are brought closer to a magnet, the nails are drawn to the magnet.
Each magnet has two poles—a north pole (N) and a south pole (S). Unlike poles (N–S or S–N) attract each other whereas like poles (N–N or S–S) repel each other.
Investigate and Discover
Experiment: To show how magnets attract iron objects.
Muscular force is used to lift weights.
Materials Needed: A magnet of any shape, iron paper clips, a sheet of paper
Method:
Step 1: Place some paper clips on a sheet of paper.
Step 2: Slowly move the magnet towards the paper clips, but don’t touch them. Note what happens.
Findings: When we move the magnet closer to the iron clips, the clips are attracted to the magnet.
Conclusion: This happens due to the magnetic force exerted by the magnet. The above experiment shows how the magnet exerts a magnetic force on iron objects.
repel: to push away
Gravitational Force
Have you ever wondered why ripe apples fall towards the ground, instead of going in any other direction? What happens when you throw a ball in air? It comes back to the ground due to gravitational force. Gravity or gravitational force is the force that attracts all objects towards the centre of the Earth.
Remember!
Gravity is what holds the planets in orbits around the Sun and what keeps the Moon in its orbit around the Earth.
falling on the ground
Sir Isaac Newton was the scientist who first discovered gravity. Did You Know?
Discuss!
Gravitational force is responsible for objects staying on the ground. What will happen if there is no gravitational force?
Frictional Force
Frictional force acts when two objects come into contact with each other. This force opposes the motion of the object. It tends to slow down the moving object and the object gradually stops. The direction of frictional force is always opposite to the direction of the motion of the object.
Frictional force depends on the nature of the surfaces. Rough surfaces offer more friction than smooth surfaces. Frictional force has some disadvantages. Some of them are:
Frictional force
Friction makes it harder for heavy objects to slide or move across a surface. Friction causes objects to wear away over time. For example, machine parts deteriorate due to friction, which is why regular oiling is needed to reduce friction and keep a machine running smoothly.
Think and Tell
Why does a ball roll smoothly on the floor but not on the grass?
Friction is not always harmful as it slows down or stops objects. It can be very useful. It helps us walk on the floor and hold different objects. If there were no friction, no moving object could ever stop on its own!
Error Alert!
Apple
Motion
Friction
Pause and Answer
Identify the type of force in each of the following.
1. Lifting a book from the table.
2. A ball thrown upwards comes back to the ground.
3. Iron nails being drawn towards a magnet.
4. Writing on the board with a chalk.
Work Done
The meaning of work in general terms is completely different from how we use the word in science. In science, work is said to be done when the position of an object changes in the direction of force applied on the object.
Let’s look at two examples to understand the concept of work better.
The child applies force to push the box on the ground.
The position of the box changes. Work is done here.
The child applies force to push the wall.
Do and Learn
The wall does not move and its position remains same.
Work is not done here.
Safely push or pull different objects present around you. Take an A4 sheet of paper and note the direction in which you applied force and the direction in which objects moved when work was done. Infer the relation between the direction of force and the work done. Share your observations with the class.
Energy: Forms and Resources
Energy is the ability to do work. We require energy for everyday activities like walking, playing, running and reading. The food we eat provides us with this energy, and our food comes from plants and animals. Both plants and animals, in turn, get their energy from the sun. Therefore, the sun is the primary source of energy on Earth.
Forms of Energy
Different forms of energy are found around us. Some of them are:
Heat Energy
Burning of fuel like wood, coal, CNG and LPG releases heat energy. Heat energy is used to cook food, run steam engines and generate electricity. We also get heat energy from the Sun.
Light Energy
The energy we get from light is called light energy. It travels from a source and helps us see things. The Sun is a natural source of light energy. Electric bulbs, tube lights and candles are some human-made sources of light.
Mechanical Energy
It is the energy of an object due to its position or motion. There are two types of mechanical energy: potential energy and kinetic energy.
The energy due to the position of the object is called potential energy and the energy of the object due to its motion is called kinetic energy.
For example, water stored at a height in a dam has potential energy due to its position. But this energy gets converted into kinetic energy when water flows down from a height.
Wind Energy
The power of wind is used to move windmills which in turn produce electricity. The windmills are also used to pump water and run grinding machines.
Solar Energy
It is the energy that we get from the Sun. Devices such as solar cookers and solar heaters convert solar energy into heat energy. Solar panels convert solar energy into electrical energy.
Geothermal Energy
It is the heat energy of the Earth. It is used to keep houses and buildings warm. This energy is used to produce electricity in geothermal power plants.
Bioenergy
It is the energy that comes from plants and animals that were once alive. Wood, animal manure (formed from animal waste) and biogas are some sources of bioenergy. Bioenergy can be used to produce heat and electricity.
Energy Resources
Energy resources can be renewable or non-renewable.
Renewable Energy Resources: These are energy sources that can be used repeatedly without running out. These resources are good for the environment because they cause less pollution than other energy sources. Solar energy, wind energy and geothermal energy are renewable energy resources.
Non-renewable resources: These are energy sources that can run out or take a very long time to form. Non-renewable resources are limited. Once they are depleted, they cannot be replaced within our lifetime. That’s why it is important to use them wisely and find other ways to make energy that won’t run out such as solar and wind energy. Examples of non-renewable energy sources are:
• Coal: It is a black rock that we burn to generate electricity. It is also used in some factories to make steel and cement. It is found deep underground and takes millions of years to form from plants that once lived in swamps. When these plants died, they were buried under layers of soil and turned into coal due to the heat and pressure of the Earth.
• Petroleum (Oil): It is a thick, black liquid, also called crude oil. We use petroleum to make petrol for cars, diesel for trucks and even to heat our homes. It is also used to make products like plastics, fertilisers and medicines. Petroleum is formed from dead plants and animals that lived in the ocean millions of years ago.
Pause and Answer
Write two examples of renewable and non-renewable energy resources.
Renewable resources:
Non-renewable resources:
biogas: a gas formed from the waste of plants and animals swamps: wetlands partially covered with water
Biogas power plant
Coal
Wonders of Bharat
Bhadla Solar Park is one of the largest solar parks in the world. It is located in the Bhadla region of Rajasthan in India. The electricity made by the solar park is sent to homes, schools and offices. This massive solar farm helps generate a significant amount of clean, renewable energy that is sent to many places in India.
Word Splash
gravity: the force that attracts every object towards the centre of the Earth potential energy: the energy due to the position of an object kinetic energy: the energy due to the movement of an object
Explore More!
Scan the QR code to learn more about force, work and energy.
Points to Remember
• Force can make an object move, stop or change its direction.
• Work is done when a force moves an object over a distance.
• Energy is available in different forms such as heat energy, light energy, wind energy, solar energy, geothermal energy and mechanical energy.
• Energy resources can be renewable or non-renewable.
Chapter Checkup
1. Tick ( ) the correct option.
A. Push or pull is an example of:
B. Solar energy comes from water the Sun
Bhadla Solar Park
C. When you lift a book, you are using wind energy muscular energy hydro energy biomass energy
D. An example of a non-renewable source of energy is: Biomass the Sun Petroleum Wind
2. Fill in the blanks.
opposite rough geothermal non-renewable renewable
A. Friction always acts to the direction of motion.
B. surfaces offer more friction than smooth surfaces.
C. Coal and petroleum are sources of energy.
D. Solar energy and wind energy are sources of energy.
E. energy is the energy of the earth.
3. Write True or False.
A. Friction slows down or stops the motion of objects.
B. Only living things can exert muscular force.
C. Solar panels convert solar energy into electrical energy.
D. Petroleum is formed from dead plants buried under oceans.
4. Short-answer questions.
A. Why does a magnet attract iron nails but not a piece of wood?
B. Write two ways in which friction is useful.
C. List the effects of force.
D. When is work said to be done?
5 Long-answer questions.
A. Explain different types of forces. Give examples of each.
B. What is mechanical energy? How is the energy of stored water in a dam related to the energy of water flowing out of a dam?
C. Write the difference between renewable and non-renewable energy resources with examples.
D. Give reasons for the following:
a. We remain grounded on the Earth’s surface.
b. A moving toy car stops after some time.
c. We should prefer using devices powered by solar energy.
6. Picture-based questions.
A. Which form of energy is used to run the objects shown in the image?
B. Is it a renewable or non-renewable energy source? Explain your answer.
Challenge (HOTS)
1. How would our life be different if there were no friction?
2. What will happen if all the non-renewable sources of energy are depleted?
Life Skills
We should use non-renewable sources of energy carefully because they are limited. It will take the Earth millions of years again to create coal or oil. Also, their overuse causes pollution, including the increase of greenhouse gases in the atmosphere, which causes more global warming and climate change, in turn.
1. What steps will you take to use non-renewable sources more efficiently?
2. Make posters to create awareness about the excessive use of non-renewable sources. Include steps that should be taken to use non-renewable sources efficiently. Display the posters in various areas of your school.
Machines Around Us
Chapter Overview
Machines Around Us
Importance of Machines
Simple and Complex Machines
Types of Simple Machines
Look at the images given below. Tick ( ) the activities where simple machines are being used. Get Set
Importance of Machines
Have you ever seen a person or a car mechanic changing the tyre of a car? Does he do it manually? No, it’s not possible for a person to lift the car without a machine called jack. It makes his job easier and faster.
manually: something done by hands Jack
Machines help us in many ways.
• Machines help us do things that we cannot do easily with our hands.
• They reduce the effort it takes to do a task.
• They help us perform the task easily and efficiently.
• They save time and energy.
Simple and Complex Machines
There are two types of machines: simple and complex.
Simple Machines: Simple machines work by changing the direction of the force or by reducing the effort needed to do a task.
Complex Machines: Complex machines are a combination of two or more simple machines working together to perform a task.
Examples in Daily Life
Rhea cut out some pictures using a pair of scissors and pasted them in a scrapbook for her science project. Her elder brother came home from his skating classes. He put his roller skates away and went to drink juice from the refrigerator. Their mother was washing clothes in the washing machine. When their father came from the office, he parked his car in the garage.
As you can see, various machines are being used. Some of them are simple while others are complex. Scissors and roller skates are examples of simple machines while refrigerators, washing machines and cars are complex machines. Some other examples of simple machines in our daily lives are knives, pliers, screws and tongs.
Think and Tell
Can you think of any other complex machine than those mentioned above?
Knife Tongs Simple machines
Washing machine Car Complex machines
Do and Learn
Look into your surroundings and observe the machines being used around you. Pick one complex machine such as a fan or a bicycle and find out how many simple machines are used to create the complex machine.
Types of Simple Machines
There are six types of simple machines that make our work easier by allowing us to apply less force. Let us discuss them in detail:
1. Lever 2. Pulley 3. Wedge
4. Wheel and axle 5. Inclined plane 6. Screw
Lever
A lever is a straight rod that rests on a fixed point and can be turned around that point. That fixed point is called the fulcrum. The force applied on a lever is called effort. The object that is moved by a lever is called the load. For example, a metal spoon used to open a tin lid acts as a lever. Some other examples of levers are scissors, bottle openers, pliers, tongs and a see-saw.
Investigate and Discover
Aim: To show the working of a lever.
Materials Required: A book, a pencil box, a table and a metal ruler
Method:
Step 1: Take a pencil box and place it on the table.
Step 2: Now, place the metal ruler on the pencil box. The part of the ruler that rests on the pencil box acts as the fulcrum.
Step 3: Place the book on one end of the ruler.
Step 4: Gently press the other end of the ruler and observe what happens. Findings: You can life the book by pressing the other end of the ruler.
Conclusion: The above experiment shows the working of a lever.
Based on the positions of the fulcrum, load and effort, levers are categorised into three classes. Let’s learn about them.
• First Class Levers: In these levers, the fulcrum is in the centre of the load and the effort. Examples of such levers are a pair of scissors, seesaws, pliers and hand pumps.
• Second Class Levers: In these levers, the load is placed between the fulcrum and the effort. Examples of second-class levers are bottle-openers, wheelbarrow and nutcrackers.
• Third Class Levers: In these levers, the effort is placed between the load and the fulcrum. Examples of such levers are forceps, tongs and fishing rods.
Pulley
A pulley is a simple machine made up of a grooved wheel with a rope around it. The heavy objects are attached at one end of the rope, while we pull the other end of the rope. It is used to lift or lower heavy objects like drawing water from wells, hoisting flags, and pulling window blinds up. There are two main types of pulleys:
grooved: with narrow cuts on the surface stationary: something at rest
Fulcrum
Seesaw First class levers
Fulcrum
A pair of tongs Third class levers
Fulcrum
A nut cracker Second class levers
1. Fixed Pulley: This type of pulley does not move and is attached to a stationary object like a hook or a wall. It changes the direction of the applied force but does not reduce the amount of force needed. Fixed pulleys are commonly used in flagpoles and water wells.
2. Movable Pulley: This type of pulley is not fixed in place; instead, it moves along with the load, reducing the effort needed to lift the load. They are often used in cranes and tow-away vehicles to lift or drag heavy objects.
Inclined Plane
Have you ever seen a wooden plank being used to load or unload goods from a truck? It is an example of an inclined plane.
An inclined plane is a surface whose one end is raised to an angle while the other end stays on the ground. It requires a lot of effort to lift something straight. But it is easier to push or roll it up an inclined plane. This makes tasks like loading or unloading heavy goods from trucks much easier. Some examples of inclined planes are ramps, slides and sloped roads.
crane
An inclined plane
flagpole
A slide
A ramp
Wedge
A wedge is a simple machine made up of two inclined planes joined back-to-back, forming a sharp edge. It is used to cut or split objects. Some common examples of wedges are knives, axes and nails.
Wheel and Axle
This simple machine has a circular part called the wheel attached to a smaller rod called an axle. The axle passes through the centre of the wheel. When the axle moves, the wheel turns around it. This simple machine makes tasks easier by reducing the amount of effort needed to move or turn objects. Some examples of wheel and axle are the steering wheel of a car, bicycle pedals, screwdrivers and wheels of roller skates.
Screw
and axle
The weight of the object remains the same when lifted manually or by using machines. Machines simply decrease the force needed to lift or move things.
A screw is a type of inclined plane that is wrapped around a straight, rod-like structure, forming a spiral. It is used to hold things together effectively. Some examples of screws include bottle caps and jackscrews. The attaching end of some light bulbs is also an example of screws. Screws
Wheel
Wheel
Axle
Error Alert!
A screw driver Skates with wheels
Wonders of Bharat
The Tata Institute of Fundamental Research Automatic Calculator (TIFRAC) was the first computer that was developed in India, at the Tata Institute of Fundamental Research in Mumbai. This machine was in use till 1965.
Word Splash
machine: a device that makes our work simpler and faster lever: a straight rod that rests on a fixed point and can be turned around that point fulcrum: a fixed point around which a lever can be turned effort: the force applied on the lever load: the object that is moved by a lever pulley: a grooved wheel with a rope around it inclined plane: a surface whose one end is raised at an angle while the other end stays on the ground wedge: it is made up of two inclined planes joined back-to-back, forming a sharp edge wheel and axle: it consists of a circular part called the wheel which is attached to a rod called an axle screw: an inclined plane wrapped around a cylinder
Explore More!
Scan the QR code to learn more about simple machines.
Points to Remember
• Machines reduce effort, increase speed, and save time and energy.
• Simple machines are machines that work by changing the direction of the force or by reducing the effort needed to do a task. Some simple machines are levers, inclined planes, wedges, pulleys and screws.
• Complex machines are a combination of two or more simple machines working together to perform a task.
• There are three types of levers—first class, second class and third class.
• There are two types of pulleys—fixed and movable pulleys.
Chapter Checkup
1. Tick ( ) the correct option.
A. Which of the following is a simple machine?
Refrigerator
Car
Washing machine
Scissors
B. Which of the following simple machine has two inclined planes joined together?
Wedge
Lever
Screw
Pulley
C. Which of these is an example of third-class lever?
A pair of tongs
Scissors
See-saw
Nutcracker
D. Which of these is an example of a movable pulley?
Hoisting a flag on a flagpole
Drawing water from a well Towing cars from cranes
E. How many types of levers are there?
One
Three
2. Match the following.
A. Inclined plane
B. Wheel and axle
Fishing rod
Two
Four
C. Pulley iii.
D. Wedge iv.
E. Lever v.
F. Screw
3. Fill in the blanks. effort complex fulcrum cylinder first-class
A. A machine is made up of two or more simple machines.
B. A screw is an inclined plane wrapped around a .
C. The is the point where a lever turns.
D. The force applied on a lever is called .
E. A pair of scissors is an example of a lever.
4. Write True or False.
A. Complex machines are made of only one simple machine.
B. A bottle opener is an example of a second-class lever.
C. A car is a complex machine.
D. There are two types of pulleys.
E. There are three types of levers.
5. Short-answer questions.
A. Give two examples of objects around you that are a wheel and axle.
B. Define the three parts of a lever.
C. How is a screw different from an inclined plane?
D. Why do we use a pulley?
E. What is a wedge? Write two examples of wedges.
6. Long-answer questions.
A. Why are machines important in our lives?
B. Differentiate between a simple and a complex machine. Give two examples of each.
C. Describe different types of pulleys with an example of each.
D. Describe different types of levers with an example of each. Support your answer with diagrams.
7. Picture-based questions.
A. Which picture shows work being done with less effort. Give reasons for your choice.
B. Name the simple machine being used in the picture you chose. Write its function as well.
Challenge (HOTS)
If you want to lift something heavy, would you choose a pulley or a ramp? Why?
Life Skills
Always use machines with care to avoid injuries. When using tools like scissors, make sure you hold them correctly and cut away from your body. Be cautious while using a knife or a can opener to avoid cutting yourself. If you need to move something heavy, like a loaded wheelbarrow, ask for help if it’s too heavy to push alone. Also, never try to fix a broken machine by yourself—always seek an adult’s help. Remember, using machines carefully will keep you and others safe.
(i)
(ii)
Light and Shadows
Chapter Overview
Light and Shadows
Luminous and Non-luminous Objects
Flow of Light Shadows
Write ‘N’ for natural sources of light and ‘H’ for human-made sources of light. Get Set
Luminous and Non-luminous Objects
Objects that give out light of their own are called luminous objects. Examples of luminous objects found in nature are the Sun and other stars. Luminous objects made by humans are torches, tube lights, candles and electric bulbs.
Objects that do not give out light of their own are known as non-luminous objects. We can see a non-luminous object only when light falls on it. Some examples of non-luminous objects are the Moon, Earth, books, walls, pillows and doors.
Think and Tell
Name three non-luminous objects in your classroom.
Pause and Answer
objects
Non-luminous objects
Sort the given objects as luminous and non-luminous objects. Fill in the table. wall door stars Sun Earth Moon pen firefly electric bulb tube light
Luminous Objects
Non-luminous Objects
Flow of Light
Have you ever wondered why you can see through some things but not others? Non-luminous objects are composed of different materials. These materials allow different amounts of light to pass through them. There are three types of objects, depending on the amount of light they let through: transparent, translucent and opaque. Let’s learn about these types.
Remember!
Light is a type of energy that helps us see things.
Transparent Materials
Roshni and her brother Rehan were playing when Roshni noticed the beautiful weather outside through their clear glass window. Rehan tells her that they can see clearly because clear glass is a transparent material. Curious, Roshni asks Rehan to explain what transparent materials are!
Luminous
(made by humans)
The materials that allow light to pass through completely, are called transparent materials. We can clearly see through transparent materials. Some examples of transparent materials are clean water and clear glass.
Translucent Materials
The materials that allow light to pass through partially are called translucent materials. Some examples of translucent materials are tissue paper, dirty water and butter paper. When we see an object through translucent materials, it appears blurred.
Opaque Materials
Materials that do not allow light to pass through them are called opaque materials. Some examples of opaque materials are cricket ball, book, wall, door and duster.
Path of Light
All light passess through
Some light passess through
No light passess through
Think and Tell
Is the human body translucent or opaque in nature? Give reasons for your answer.
Light travels in a straight line and cannot bend around objects. You can see this when sunlight passes through a window or when you shine a torch in a dark room. The straight path of light helps us understand how we see objects.
Investigate and Discover
Experiment: To show that light travels in a straight line.
Materials Needed: A candle, matchbox/lighter and a flexible plastic tube
Method:
Step 1: Take a flexible plastic tube that measures around 10 inches.
Step 2: Light a candle with a lighter. (Ask an adult to help you.)
Step 3: Now, point one end of the plastic tube at the source of light. Hold the tube straight.
Step 4: Place your eyes on the other side of the tube. You will see the candle.
partially: only part of blurred: unclear
Step 5: Now, bend the plastic tube and try to look through it. This time you will not see the candle.
Findings: When you try to see through the bent tube, you cannot see the candle. But the candle is visible when the tube is kept in a straight position.
Conclusion: The above experiment shows that light travels in a straight line.
Shadows
A shadow is a dark area formed when an object blocks the path of light. Light sources like the Sun, electric bulbs and torches create shadows is kept. Trees, books, and buildings can make shadows.
For a shadow to form, you need a light source, an object to block the light and a surface for the shadow to appear on.
All objects don’t form shadows. Only opaque and translucent objects form shadows. Transparent objects cannot form shadows. Error Alert!
Features of Shadows
Some features of a shadow are:
• A shadow is always formed on the opposite side of the source of light.
• A shadow is always black, no matter what the colour of the object is.
source
• The shape and size of your shadow change depending on the position of the light source and the surface on which it is formed. In the morning and evening, your shadow is longer because the Sun’s rays fall on you at an angle. At noon,
Light source
Formation of a shadow
when the Sun is high in the sky, your shadow is shorter because the Sun’s rays are straight.
Discuss!
Can we see our shadow in a dark room? Why or why not? Discuss with your classmates.
Do and Learn
Shadow changes with the position of light source. Morning Noon Evening
Plan a day at the park. Choose any one object that you find in the park and observe its shadow. Measure the length of the shadows created by the object at different times of the day. Do you observe any change in the lengths?
Wonders of Bharat
Shadow puppetry, known as Tholu Bommalatta, is an ancient form of storytelling, particularly in Andhra Pradesh. This traditional art form uses flat, articulated figures to create shadows on a screen, bringing stories and folklore to life.
Word Splash
luminous objects: objects that give out light of their own non-luminous objects: objects that do not give out their own light transparent: materials that allow light to pass through them completely translucent: materials that allow light to pass through them partially opaque: materials that don’t allow light to pass through them shadow: a dark area formed when an object blocks light from the light source
Explore More!
Scan the QR code to learn more about light and shadows.
Points to Remember
• Luminous objects give out their own light, while non-luminous objects don’t.
• Non-luminous objects can be transparent, translucent, or opaque.
• Shadows are formed when an object blocks light from the light source.
• Shadows need a light source, an object to block the light, and a surface to appear on.
Chapter Checkup
1. Tick ( ) the correct option.
A. Which of the following is a luminous object?
Book Sun Plastic Wood
B. Which of the following is a non-luminous object?
Sun Star Candle Wood
C. Which of the following is an example of a transparent material?
Wooden door
Frosted glass
D. Which of the following materials is opaque?
Tissue paper
E. Light travels in a:
Curved path
2. Fill in the blanks.
Butter paper
Straight line
Clear glass
Metal sheet
Wooden door
Clear plastic
Circular path
Zigzag line
black transparent longer shadows translucent
A. materials allow light to pass through partially.
B. are formed when an object blocks light.
C. objects don’t form any shadow.
D. Shadows are always .
E. In the morning and evening, shadows are .
3. Write True or False.
A. Opaque materials allow some light to pass through.
B. A transparent object makes a clear shadow.
C. Shadows are formed when light is absorbed by an object.
D. Shadows are colourful and change colour with the object.
E. The length of the shadow is always the same as that of the object.
4. Short-answer questions.
A. How is the Moon different from the Sun?
B. What are the three types of non-luminous objects?
C. How are shadows formed?
D. What happens to the size of a shadow when the light source moves?
5. Long-answer questions.
A. How are luminous objects different from non-luminous objects? Give examples for each.
B. What are transparent, translucent and opaque materials? Give examples of each.
C. Explain how the position of the Sun affects the length and direction of shadows.
D. List any three properties of shadows.
6. Picture-based questions.
A. Identify the object and the source of light in the given image.
B. What do you notice about the shadows? Why do you think that happens?
Challenge (HOTS)
Can you think of a situation where shadows can be helpful in daily life?
Give 1–2 examples.
The Moon and the Eclipse 15
Chapter Overview
The Moon and the Eclipse Moon Around the Earth Eclipses Tides
Phases of the Moon
INTEGRATED Get Set
Solve the following riddles!
You’ll see me at night but never at noon.
I’m not a star, but I’m still a boon.
What am I?
You’ll see me at day and noon but never at night.
I’m a shiny star that shines very bright. What am I?
Moon Around the Earth
The Moon is the Earth’s closest neighbour in space. Unlike the Sun, the Moon doesn’t have its own light. Instead, it reflects the Sun’s light, which is why it appears bright at night. The Moon is one of the brightest objects in the sky after the Sun.
Located about 3,84,400 kilometres away from Earth, the Moon is smaller than both the Earth and the Sun. It appears similar in size to the Sun because it is nearer to us.
Surface of the Moon
Imagine a dry and dusty playground covered with holes – that’s what the Moon’s surface looks like! Have you ever wondered why the surface of the Moon is rough and uneven? This is because it is made up of rocks. The Moon’s surface is dry, rough, and uneven, and is covered by a layer of dust. It features mountains, lava plains, valleys, and craters. The craters are deep holes created by meteorites colliding with the Moon’s surface. There are millions of these craters, formed billions of years ago. Like Earth, the Moon has gravity, which is about one-sixth compared to Earth’s. The tides in the seas and oceans on Earth are influenced by the Moon’s gravitational force, causing high and low tides.
Atmosphere on the Moon
The Moon does not have an atmosphere like that of the Earth. The Earth’s atmosphere has oxygen, which we need to breathe. The Earth’s atmosphere protects us from the Sun’s harmful UV rays. The Moon, however, has a very thin layer called an exosphere, which is not thick enough to support life or give protection from the Sun’s radiation. This thin exosphere exists because the Moon’s gravity is too weak to hold onto a thicker atmosphere. As a result, there is no air to breathe on the Moon, and the surface is exposed to extreme temperatures (scorching hot days and freezing cold nights). We cannot hear any sound on the moon as it has no air.
Phases of the Moon
Have you ever looked up at the night sky and noticed that the Moon looks different each night? Sometimes it looks like a thin half-circle or sometimes like a full circle. The ever-changing appearance or the shapes of the Moon are called its phases. There are 8 phases of the moon. It takes 29.5 days to completely cycle through all these phases. This is known as the lunar month.
We always see the same side of the Moon because the Moon’s revolution around the Earth and its rotation on its axis occur at the same speed. As the Moon revolves and rotates, it appears to change shape each day, transitioning from a thin crescent to a full moon. This variation occurs because the side of the moon facing us receives different amounts of sunlight as it moves in its orbit around the Earth.
Surface of the Moon
Let’s learn about the different phases of the Moon that appear in its monthly journey.
1. New Moon: The Moon is between Earth and the Sun. Sunlight can’t reach the side facing Earth, so the Moon appears completely dark.
2. Waxing Crescent Moon: The Moon continues in its orbit, and a small crescent becomes visible.The Sun’s light hits a small portion of the side facing Earth, creating a thin lit-up area.
3. First Quarter or Half Moon: Half of the Moon is illuminated by the Sun, appearing as a semi-circle. “First quarter” refers to the Moon being one-quarter through its orbit.
4. Waxing Gibbous Moon: More than half of the Moon is illuminated, but it’s not yet a full circle. The illuminated portion grows larger each night.
5. Full Moon: The Moon is on the opposite side of Earth from the Sun. The side facing Earth is fully lit by sunlight.
6. Waning Gibbous Moon: After the full moon, the illuminated part starts to shrink. The lit portion decreases as the Moon moves toward the third quarter.
7. Third Quarter Moon: Another half of the Moon is illuminated, but it’s the opposite side from the first quarter. The Moon is now three-quarters through its orbit.
8. Waning Crescent: The Moon becomes a thin crescent again, with the curved side facing the opposite direction. The lit area gradually shrinks until the cycle restarts.
Do and Learn
Throughout the month, observe the Moon each night and sketch what you see in a journal. Record the date, time, and details about the Moon’s shape and brightness. This will help you track the gradual changes in its phases.
crescent: the shape of the Moon less than half illuminated illuminated: made bright with light waxing: when the Moon’s apparent shape is thickening waning: when the Moon’s apparent shape is thinning
Phases of the Moon
Pause and Answer
Look at the images given below and identify each phase of the Moon.
Eclipses
An eclipse occurs when the Sun’s light is partially or completely blocked by the Earth or the Moon. Both the Earth and the Moon are composed of rocks, and they do not allow light to pass through. When light hits an opaque object, it casts a shadow. As we know, the Earth revolves around the Sun, while the Moon orbits the Earth. At certain times, the Sun, Moon, and Earth align in a straight line. In this arrangement, the sunlight is obstructed by the celestial object in the middle, causing its shadow to fall on the object that is eclipsed. Depending on which celestial body is blocked, eclipses are classified into two types: solar eclipses and lunar eclipses. Let us learn about each of them.
Solar Eclipse
Imagine the Earth, the Moon, and the Sun in a perfect line. In this eclipse, the Moon comes in between the Sun and the Earth. Due to this, the Moon casts a shadow on Earth’s surface. People standing in the path of this shadow experience a partial or complete blackout of the Sun for a short time.
There are two main types of solar eclipses:
Total Solar Eclipse: The Moon completely blocks the Sun, creating a brief period of darkness during the day. During this eclipse, we cannot see the Sun.
partial: not complete
Remember!
The objects that don’t allow the light to pass through them are called opaque objects. When light falls on such objects, these cast a shadow.
Solar eclipse
Did You Know?
During a solar eclipse, we should not look at the Sun with our naked eyes as it is harmful.
Partial Solar Eclipse: The Moon only covers part of the Sun, so the Sun appears to have a dark bite taken out of it.
During a solar eclipse, two types of shadows are cast by the Moon: the umbra and the penumbra. The umbra is the central, darkest part of the shadow where the Sun is completely blocked by the Moon, causing a total eclipse for those in this area. The penumbra is the outer part of the shadow where only a part of the Sun is covered by the Moon, resulting in a partial eclipse for those in this region.
Think and Tell
During which phase of the Moon can a solar eclipse occur, and why?
Lunar Eclipse
During a lunar eclipse, the Earth is between the Sun and the Moon. The Earth casts a shadow on the Moon, blocking the sunlight that usually reflects off its surface. From Earth, the Moon appears to darken or turn a reddish colour. This happens because of the indirect sunlight filtering through the Earth’s atmosphere. A lunar eclipse typically lasts for about an hour or so.
eclipse
During a lunar eclipse, two types of shadows are cast by the Earth: the umbra and the penumbra. The umbra is the central, darkest part of the shadow where the Moon is completely covered, causing a total or partial eclipse. The penumbra is the outer part of the shadow where only a part of the sunlight is blocked.
There are two main types of lunar eclipses:
Total Lunar Eclipse: The entire Moon passes through the Earth’s umbra, the central, darkest part of its shadow. During a total lunar eclipse, the Moon can appear deep red or coppery.
Partial Lunar Eclipse: Only a part of the Moon passes through the Earth’s umbra, while the rest remains in the penumbra. During a partial lunar eclipse, part of the Moon appears darkened.
Some people observe traditional practices around the time of eclipses. It is important to share that solar and lunar eclipses are natural events caused by the regular movements of the Earth, Moon, and Sun in space. One should not feel scared or anxious.
Lunar
Investigate and Discover
Aim: To demonstrate how a lunar eclipse occurs using simple materials.
Materials Needed: flashlight (to represent the Sun), a small tennis ball (to represent the Moon), and a large ball/globe (to represent the Earth), pen and paper
Method:
Step 1: Turn on the flashlight in a dark room. This flashlight will act as the Sun.
Step 2: Place the larger ball (Earth) a few feet away from the flashlight. Make sure it is in line with the flashlight.
Step 3: Hold the smaller ball (Moon) in your hand.
Step 4: Move the Moon to the opposite side of the Earth, away from the Sun. Now, position the Earth between the Sun and the Moon, making sure the shadow of the Earth falls on the Moon.
Step 5: Observe what happens.
Findings: When a larger ball (Earth) comes in between the flashlight (Sun) and the smaller ball (Moon), it blocks the flashlight from reaching the Moon. Therefore, the larger ball casts its shadow on the smaller ball.
Conclusion: The above experiment shows that the lunar eclipse takes place when the Earth, the Moon and the Sun are present in a line and the Earth comes in between the Sun and the Moon.
Tides
The periodic rise and fall of sea or ocean water is called a tide. The formation of tides occurs due to the Moon’s gravity.
As the Moon orbits the Earth, the side of the Earth facing the Moon experiences the strongest gravitational pull. This causes the water to rise on that side, resulting in high tides along the shores. Interestingly, high tides also occur on the opposite side of the Earth due to the combined effects of the Earth’s rotation and the Moon’s gravitational force. Between these high tides, the water level in the oceans decreases, resulting in low tides (when the water level recedes).
Wonders of Bharat
The town of Kutch in Gujarat is renowned for its breathtaking views of the Moon, especially during the Rann Utsav. The vast white salt desert, known as the Rann of Kutch, reflects the moonlight in a mesmerising way, creating a magical landscape. During full moon nights, the entire salt desert shimmers under the moonlight, offering a unique and unforgettable experience.
Word Splash
Rann of Kutch
meteorites: space rocks that fall on Earth, Moon or other planets exosphere: the thin layer of the Moon’s atmosphere gravity: the force that attracts objects towards the centre of the Earth umbra: the dark part of the shadow penumbra: the part of a shadow that’s a little lighter tides: the rise and fall of ocean levels caused by the Moon’s gravity
Explore More!
Scan the QR code to learn more about the phases of the Moon.
Points to Remember
• The Moon has no light of its own. It reflects sunlight which is why it appears bright at night.
• The surface of the Moon is rough and uneven with craters on it.
• The different shapes of the Moon are called its phases.
• An eclipse occurs when the Sun’s light is blocked either by the Moon or the Earth.
• The periodic rise and fall of water due to gravitational forces between the Moon and the Earth is called a tide.
Chapter Checkup
1. Tick ( ) the correct option.
A. During which phase of the Moon is the entire side facing Earth lit up by the Sun?
New Moon Waxing Crescent
Full Moon Waning Gibbous
B. What is the main reason we experience tides on Earth?
The Sun’s gravity pulling on the oceans
The Moon’s gravity pulling on the oceans
The rotation of Earth on its axis
The Earth’s gravity pulls the oceans
C. Which of the following is true about a lunar eclipse?
The Moon is between the Earth and the Sun.
The Earth is between the Sun and the Moon.
The Sun is between the Earth and the Moon.
The Moon completely blocks the Sun.
2. Fill in the blanks.
A. The is the thin layer of gases surrounding the Moon.
B. The different shapes of the Moon we see throughout the month are called its .
C. A eclipse occurs when the Earth casts a shadow on the Moon.
D. The formation of occurs due to Moon’s gravity.
3. Write True or False.
A. The surface of the Moon is rough and uneven.
B. A solar eclipse occurs when the Moon comes between the Earth and the Sun.
C. Lunar eclipse occurs for a short time duration.
D. The periodic rise and fall of ocean water is called a tide.
4. Circle the correct alternative in each of the following.
A. The Moon / Sun does not have its own light.
B. The Moon has a very thin layer of gases called atmosphere / exosphere.
C. The ever-changing shapes of the Moon are called its phases / tides.
D. The Moon comes in between the Sun and the Earth in solar / lunar eclipse.
5. Short-answer questions.
A. Briefly describe the surface of the Moon.
B. How does the Moon differ from the Earth in terms of atmosphere?
C. Why does the Moon change its shape throughout the month?
D. How does the Moon’s gravity affect the tides on Earth?
6. Long-answer questions.
A. Explain how different phases of the Moon occur.
B. How is a solar eclipse different from a lunar eclipse? Explain with the help of well-labelled diagrams.
C. Differentiate between a partial and a total solar eclipse.
7. Picture-based questions.
A. What is depicted in Image 1?
B. What is depicted in Image 2?
Challenge (HOTS)
Imagine you are planning to observe a solar eclipse from your school playground. What tools or safety measures would you use to safely watch the eclipse?
Image 1
Image 2
Life Skills
The New Moon is a time of new beginnings in many cultures. Let’s explore how people in different parts of India celebrate and acknowledge this lunar phase!
• Start by choosing a city/state (or a few) to research. You can use the map of India to pick a place that interests you or ask an adult to suggest some options.
• Once you have your location(s), use the internet or ask an adult to help you find out:
⸰ How do people in this place celebrate or acknowledge the New Moon?
⸰ Are there any special stories or folktales related to it?
Share your findings with your family or friends!
PROJECT 3 Friction Race!
Objective: Students will understand how different surfaces offer frictional force and apply this knowledge practically.
Materials Needed: Toy car, a pen, a notebook, a ruler, a carpet, a wooden board, a plastic sheet, aluminium foil, a towel
Step 1: Learn about Friction
Understand what friction is and how it affects the movement of objects. Use your textbook or online resources to learn about how different surfaces can create varying levels of friction.
Step 2: Test the Car
Push the toy car on each surface (carpet, wooden board, plastic sheet, aluminium foil and a towel). Observe and note how far the car travels on each surface.
Step 3: Record Distances and Create a Table
Use a ruler to measure the distance. Draw a table in your notebook like this:
Surface
Carpet
Wooden board
Plastic sheet
Aluminium foil
Towel
Fill in the distances you measured for each surface.
Step 4: Share and Discuss
Distance covered (cm)
Present your findings recorded in the table to the class. Use your recorded data to describe how friction varies with different materials.
Project Output: Now, you have a table showing how the toy car performed on each surface.
Final Outcome: This hands-on project will help you understand how frictional force affects the movement of objects.
To be read aloud and explained in the mother tongue by the teacher, as needed.
Assessment 3
Read this article. Answer the questions given below.
Exploring Moon!
One night, Aria sat by her window, gazing up at the glowing Moon. She was curious about what it would be like to visit this bright, mysterious place. Her father, noticing her interest, sat down beside her.
“Did you know, the Moon’s surface is full of craters?” he said. “These craters were formed when meteorites crashed into its surface, long, long ago.”
Aria’s eyes widened. “Why doesn’t it look like Earth?” she wondered.
“Well,” her father explained, “the Moon is very different. It has a thin exosphere, so it can’t hold onto heat like the Earth can. During the day, the Moon becomes really hot, but at night, it gets freezing cold. That’s why life can’t flourish there. Imagine living in a place where it’s scorching hot one minute and icy cold the next!”
“Wow,” Aria said, her imagination running wild, “It must be so lonely up there.”
Her father smiled. “Yes, it’s a beautiful but harsh place. That’s what makes it so fascinating. It’s not like home, but it helps us learn more about the universe.”
1. What is the Moon’s surface covered with?
A. Comets
B. Stars
C. Craters
2. Why does the Moon have extreme temperature changes?
A. It has a thin exosphere.
B. It is very close to the Sun.
C. It is made up of ice and snow.
3. Why is life difficult on the Moon? Give two reasons for your answer.
4. Imagine you are an astronaut visiting the Moon. Mention any three items you would bring to stay safe and comfortable, considering the Moon’s surface and atmosphere. Explain your choices in 3–4 sentences.
To be read aloud and explained in the mother tongue by the teacher, as needed.
Craters on the Moon
About the Book
Introducing Reflection, a thoughtfully crafted Science book that ignites curiosity, and nurtures a love for enquiry and evidence-based thinking, in young minds. In keeping with National Education Policy (NEP) 2020’s focus on competency-based education, Reflection provides opportunities for learners to master core scientific concepts, develop a scientific temper, hone their critical thinking, and apply 21st century skills in their day-to-day lives. Reflection is designed to fascinate students towards science, both as a subject and as a practical experience, while also making them well-rounded individuals.
Product Package
• Coursebook
• Uolo App
• Teacher’s Guide
Key Features
• STEAM Projects: Engaging, hands-on projects blending Science, Technology, Engineering, Art and Maths (STEAM) to inspire young minds
• Competency-based Assessments: Test papers designed to evaluate the understanding of core concepts and application of skills
• Story-based Approach: Enchanting comic stories that bring learning themes to life, making education a captivating adventure
• Investigate and Discover: Hands-on experiments to foster the spirit of scientific enquiry and evidence-based thinking
• Picture-based Questions: Questions featuring visual stimuli to elevate comprehension, interpretation and critical thinking
• Wonders of Bharat: Fascinating insights into India’s rich culture and heritage, designed to ignite a profound sense of pride and love for the nation
About Uolo
Uolo partners with K-12 schools to provide technology-based learning programs. We believe pedagogy and technology must come together to deliver scalable learning experiences that generate measurable outcomes. Uolo is trusted by over 15,000+ schools across India, South East Asia and the Middle East.
ISBN 978-81-979832-7-6
