Living things are different from non-living things because they grow, breathe, take food, respond to their surroundings, get rid of waste, move and produce young ones. This chapter explains each of these characteristics with simple examples.
Key points
Every living thing needs air, food and water. Food gives energy for growth.
Growth is increase in size, height and weight. Development is progress in body, intelligence, skills and work capacity.
Animals grow only for a certain period of life. Plants keep growing as long as they are alive (girth of trunk, branches, roots).
Plants make their own food by photosynthesis. Animals depend on plants or other animals.
Sensing the surroundings is a stimulus; the way the living thing acts is the response. Plants also respond (lotus buds open in sunlight).
Removing waste from the body is excretion. Animals: sweat, urine, faeces. Plants: shedding leaves, bark, gum.
Making energy in the body using oxygen and food is respiration. Breathing in is inhalation; breathing out is exhalation.
Animals move from place to place. Plants cannot, but their parts move (roots grow, leaves open and close).
Producing young ones like oneself is reproduction. A seed growing into a plant is germination.
Growth and reproduction are the main characteristics of living things.
Changes in body form during growth (e.g. egg → larva → pupa → adult in a butterfly) are called the life cycle or metamorphosis.
Important terms
Stimulus / Response – a change sensed / the reaction to it.
Excretion (उत्सर्जन) – removal of waste from the body.
Respiration (श्वसन) – producing energy from food using oxygen.
Reproduction (प्रजनन) – producing young ones.
Germination (अंकुरण) – a seed growing into a plant.
Key facts
Characteristic
Plant example
Animal example
Excretion
Shedding leaves, gum
Sweat, urine
Movement
Leaves open and close
Walking, flying
Reproduction
Seeds
Eggs, young ones
5 important questions
Q1. What is the difference between growth and development?
Growth is increase in size and weight. Development is progress in body, intelligence and skills.
Q2. What is stimulus and response? Give an example.
Sensing a change is a stimulus; acting on it is a response. Pigeons fly away (response) on hearing firecrackers (stimulus).
Q3. How do plants get rid of waste?
By shedding leaves and bark, and by giving out gum.
Q4. A tractor and a bird can both change position. How are they different?
A bird moves on its own using its own energy; a tractor needs a driver and fuel.
Q5. Which are the main characteristics of living things?
Growth and reproduction.
Exam tip
Give one plant and one animal example for each characteristic.
Measurement means finding the size or amount of something with a suitable tool and unit. This chapter explains non-standard and standard units, the SI unit of length, the reference point, and how temperature is measured with thermometers.
Key points
Measuring with a suitable tool is measurement. The unit in which it is expressed is the unit of measurement.
In the past, people used body parts like hand span or foot. These differ from person to person, so they are non-standard units.
Today we use standard units so that measurements are the same everywhere.
The SI unit of length is the metre (m).
The fixed point from which a distance is measured is the reference point (e.g. the zero mark of a scale).
While measuring with a scale, keep the eye straight above the mark.
A thermometer measures temperature.
Temperature units: degree Celsius (°C), degree Fahrenheit (°F) and kelvin (K).
Thermometers use mercury or coloured alcohol. Digital or infrared thermometers measure body temperature.
Important terms
Measurement (मापन) – finding size or quantity with a tool.
Standard unit – a unit that is the same everywhere.
SI unit – unit of the International System of Units.
Reference point – starting point for measuring distance.
Thermometer (तापमापी) – instrument to measure temperature.
Formulas
1 km = 1000 m; 1 m = 100 cm; 1 cm = 10 mm
SI unit of length: metre (m). SI unit of temperature: kelvin (K).
Normal human body temperature ≈ 37 °C.
5 important questions
Q1. Why are body-part units like a hand span not reliable?
They are different for different people, so the measurement changes.
Q2. What is the SI unit of length?
The metre (m).
Q3. Convert 3.5 km into metres.
3.5 × 1000 = 3500 m.
Q4. What is a reference point?
The fixed point from which a distance or length is measured.
Q5. Which liquids are used in thermometers?
Mercury or coloured alcohol.
Exam tip
Learn the unit conversions; they are asked as short numericals.
A mixture has two or more substances mixed together. This chapter explains how we separate them using differences in their properties — handpicking, winnowing, sieving, filtration, sedimentation and decantation, evaporation and using a magnet.
Key points
Separating substances from a mixture is called separation.
Each method uses a difference in properties like size, weight, colour or solubility.
Handpicking: picking out stones or husk from grains by colour and shape.
Winnowing: wind blows away light husk; heavy grains fall down.
Sieving: a mesh lets small particles pass and holds big ones (flour and bran).
Sedimentation: heavy insoluble particles settle at the bottom of a liquid. Pouring off the clear liquid is decantation.
Filtration: separates undissolved solids from a liquid using filter paper or cloth.
Evaporation: changing a liquid into gas. Sea salt is obtained by evaporating seawater.
Magnetic substances like iron filings are separated using a magnet.
Important terms
Mixture (मिश्रण) – two or more substances mixed together.
Winnowing – separating husk from grain using wind.
Sieving – separating by size using a mesh.
Sedimentation – settling of heavy particles.
Decantation – pouring off clear liquid.
Evaporation (बाष्पीभवन) – liquid changing into vapour.
Key facts
Mixture
Method
Stones in rice
Handpicking
Husk and grain
Winnowing
Flour and bran
Sieving
Muddy water
Sedimentation, decantation, filtration
Salt from seawater
Evaporation
Iron filings and sand
Magnet
5 important questions
Q1. What is separation?
Separating the different substances from a mixture.
Q2. How is winnowing done?
Grain mixed with husk is dropped from a height in the wind; light husk blows away and heavy grain falls down.
Q3. How will you get clean water from muddy water?
Let the mud settle (sedimentation), pour off the water (decantation) and filter it.
Q4. How is salt obtained from seawater?
Seawater is kept in shallow pans; the water evaporates in sunlight and salt is left.
Q5. How can iron filings be separated from sand?
By moving a magnet over the mixture; iron filings stick to it.
Exam tip
For each mixture, name the method and the property it uses.
There is huge variety (diversity) among plants and animals. This chapter explains how plants are grouped by their stems, seeds, leaves and roots, and how plants and animals live in different habitats.
Key points
Main parts of a plant: root, stem, leaves and flowers.
Plants are classified by height, type of stem, leaf shape, cotyledons in seeds, presence of flowers and type of roots.
By stem: trees (thick woody trunk), shrubs (bushy, woody), herbs (small, soft stem), climbers (climb with support) and creepers (spread on the ground).
Seeds with one cotyledon are monocots (maize, wheat, rice). Seeds with two are dicots (bean, gram, groundnut).
Leaf venation is of two types: reticulate (net-like) in dicots and parallel in monocots.
Dicots usually have a taproot; monocots have fibrous roots.
Some plants have flowers; some like ferns and mosses do not.
The place where a living thing lives naturally is its habitat (pond, desert, forest, sea).
Important terms
Diversity (विविधता) – variety among living things.
Cotyledon (बीजपत्र) – seed leaf that stores food.
Venation – pattern of veins in a leaf.
Taproot / Fibrous root – one main root / many thin roots.
Habitat (अधिवास) – natural home of a living thing.
Key facts
Feature
Monocot
Dicot
Cotyledons
One
Two
Venation
Parallel
Reticulate
Roots
Fibrous
Taproot
Example
Maize, wheat
Bean, mango
5 important questions
Q1. Name the groups of plants based on their stems.
Trees, shrubs, herbs, climbers and creepers.
Q2. What are monocots and dicots?
Plants whose seeds have one cotyledon are monocots; those with two cotyledons are dicots.
Q3. How can you tell a monocot from its leaf?
Its leaf has parallel venation.
Q4. What is a habitat?
The natural surroundings where a plant or animal lives and gets what it needs.
Q5. Give two examples each of climbers and creepers.
A disaster is a sudden, serious event that causes great loss of life and property. This chapter explains natural and man-made disasters, what to do during them, and basic first aid for common emergencies.
Key points
A disaster is a sudden critical situation that comes without warning.
Natural disasters: earthquakes, river floods, storms (cyclones), forest fires.
Man-made disasters: accidents (rail, road, industrial), war, cyber crimes.
The strength (magnitude) of an earthquake is measured on the Richter scale.
During an earthquake, take cover under a strong table, keep away from glass and walls, and move to an open place after the shaking stops.
During floods, move to higher ground and do not walk or drive through flowing water.
Forest fires burn huge areas every year, destroy wildlife habitats and cause pollution.
First aid is the immediate help given to an injured or ill person before a doctor arrives. It can save lives and prevent infection.
Burns: cool with clean water; do not burst blisters.
Sunstroke: make the person sit in the shade, give water and get medical help.
Snakebite: keep the person calm, give emotional support and take them to hospital quickly.
Dog bite: wash the wound again and again with clean water and see a doctor.
Important terms
Disaster (आपत्ती) – a sudden event causing heavy loss.
Disaster management – planning to prevent, face and recover from disasters.
Richter scale – scale to measure an earthquake's strength.
First aid (प्रथमोपचार) – immediate help to an injured person.
Key facts
Natural
Man-made
Earthquake
Accidents
Flood
War
Storm
Cyber crime
Forest fire
Industrial accidents
5 important questions
Q1. What is a disaster?
A sudden, unexpected situation that causes heavy loss of life and property.
Q2. Give two examples each of natural and man-made disasters.
Natural: earthquake, flood. Man-made: railway accident, war.
Q3. On which scale is an earthquake measured?
The Richter scale.
Q4. What is first aid? Why is it important?
Immediate help given to an injured person; it can save life, reduce injury and prevent infection.
Q5. What first aid will you give for a dog bite?
Wash the wound repeatedly with clean water and take the person to a doctor.
Exam tip
Learn first aid for burns, sunstroke, snakebite and dog bite as short points.
Everything around us is made of matter, and matter is made of particles. This chapter explains objects and substances, the states of matter, change of state, transparency, and density.
Key points
Things named by their shape and use are objects (chair). The material they are made of is the substance (wood, iron, plastic).
All substances are made of tiny particles. Matter means 'made up of particles'.
Matter occupies space and has mass.
States of matter: solid, liquid and gas. In the sun, stars and lightning there is a fourth state called plasma.
In solids, particles are tightly bound; in liquids, loosely bound; in gases, very loosely bound and spread far.
The state depends on how tightly the particles are bound.
Changing from one state to another (ice → water → vapour) is a change of state. Solid carbon dioxide is called dry ice.
Transparent substances let light pass (glass). Translucent let a little light pass (butter paper). Opaque let no light pass (wood).
Mass is measured in grams or kilograms.
Density is the mass of 1 cubic centimetre of a substance.
Important terms
Matter (द्रव्य) – anything that has mass and occupies space.
Plasma – a state of matter found in stars and lightning.
Transparent / Translucent / Opaque – lets all / some / no light pass.
Density (घनता) – mass per unit volume.
Formulas
Density = Mass ÷ Volume
Unit of density: g/cm³ (grams per cubic centimetre). Mass in g or kg; volume in cm³.
5 important questions
Q1. What is the difference between an object and a substance?
An object is named by its shape and use (chair). A substance is the material it is made from (wood).
Q2. Name the states of matter.
Solid, liquid, gas and plasma.
Q3. Why does a solid have a fixed shape?
Its particles are tightly bound to each other.
Q4. Classify: glass, wood, butter paper.
Glass – transparent; butter paper – translucent; wood – opaque.
Q5. A block has mass 60 g and volume 20 cm³. Find its density.
Density = 60 ÷ 20 = 3 g/cm³.
Exam tip
Remember the density formula and its unit; practise one small numerical.
Light is a form of energy that helps us see. This chapter explains sources of light, how light travels in straight lines (pinhole camera), reflection of light, its laws, and regular and irregular reflection.
Light travels in a straight line. It does not need a medium; it can travel through empty space.
A pinhole camera works because light travels in straight lines. It forms an upside-down image.
When light falls on a surface and bounces back, it is called reflection.
The ray falling on the surface is the incident ray; the ray bouncing back is the reflected ray. The normal is a line perpendicular to the surface at that point.
Laws of reflection: (1) incident ray and reflected ray are on opposite sides of the normal; (2) angle of incidence = angle of reflection; (3) incident ray, reflected ray and normal lie in the same plane.
Reflection from smooth shiny surfaces like mirrors is regular reflection.
Reflection from rough surfaces is irregular reflection. We see objects around us because of irregular reflection.
Important terms
Luminous object – gives its own light (sun).
Reflection (परावर्तन) – bouncing back of light.
Incident ray / Reflected ray – ray falling on / bouncing off a surface.
Normal – line perpendicular to the surface at the point of incidence.
Pinhole camera – a simple box camera with a tiny hole.
Formulas
Angle of incidence (i) = Angle of reflection (r)
5 important questions
Q1. Give two natural and two man-made sources of light.
Natural: sun, stars. Man-made: bulb, torch.
Q2. Which property of light does a pinhole camera use?
Light travels in a straight line.
Q3. State the laws of reflection.
Incident and reflected rays are on opposite sides of the normal; angle of incidence equals angle of reflection; incident ray, reflected ray and normal lie in one plane.
Q4. If the angle of incidence is 35°, what is the angle of reflection?
35°, because both are always equal.
Q5. Why can we see a book lying on a table?
Light falling on its rough surface is reflected irregularly in all directions and reaches our eyes.
Exam tip
Draw a neat ray diagram with the normal, incident ray, reflected ray, i and r.
Humans have always been curious about the stars and planets. This chapter explains the difference between sky and space, constellations, comets, meteors, galaxies and the universe, and India's space research through ISRO.
Key points
The atmosphere is a thick envelope of air around the earth. At about 100 km above the earth, air becomes very thin and then ends.
The region around the earth where the atmosphere exists is the sky. The empty region beyond it is space.
Clouds, lightning and aeroplanes are in the sky. Stars, the moon and comets are far away in space.
Telescopes began to be used to observe stars and planets around 400 years ago, in 1609.
A group of stars with a fixed shape and arrangement is a constellation (nakshatra). Farmers' sayings link nakshatras with rain and crops.
Comets are made of dust, frozen gases and ice. Some orbit the sun and then go far away into space.
A bright streak in the night sky, like a falling star, is a meteor.
Every star gives out light and heat like the sun.
Our solar system is a tiny part of a huge galaxy. The universe has billions of galaxies.
ISRO (Indian Space Research Organisation) carries out many space missions.
Important terms
Sky (आकाश) – region around the earth where the atmosphere exists.
Space (अंतराळ) – empty region beyond the atmosphere.
Constellation (नक्षत्र) – a group of stars with a fixed pattern.
Comet (धूमकेतू) – a body of dust, ice and frozen gases moving around the sun.
Galaxy (दीर्घिका) – a huge group of billions of stars.
Key facts
Atmosphere ends roughly 100 km above the earth.
Telescopes used for sky-watching since 1609.
Comet Shoemaker–Levy 9 broke up and crashed into Jupiter in July 1994.
5 important questions
Q1. What is the difference between the sky and space?
The sky is the region around the earth with atmosphere; space is the empty region beyond it.
Q2. What is a constellation?
A group of stars that always has a fixed shape and arrangement.
Q3. What are comets made of?
Dust, frozen gases and ice.
Q4. What is a meteor?
A bright streak seen in the night sky, looking like a falling star.
Q5. What is a galaxy?
A huge system of billions of stars; our solar system is a small part of one.
Exam tip
Arrange in order of size: earth → solar system → galaxy → universe.
The food we eat regularly is our diet. This chapter explains regional diets, variety in food, nutrients, millets, deficiency diseases and how to cook food so that its nutrients are not lost.
Key points
Food gives us nutrition and energy to work, play, study and stay healthy.
The food we eat regularly is our diet. A diet based on local crops and climate is a regional diet.
Variety in diet comes from seasons, needs, ingredients, cooking methods and festival foods.
Nutrients are needed for growth, energy and good health: carbohydrates, proteins, fats, vitamins, minerals, water and fibre.
Millets (jowar, bajra, ragi) are rich in nutrients and should be part of our diet.
Lack of a nutrient in the diet causes deficiency diseases.
Goitre – lack of iodine (use iodized salt). Rickets – lack of vitamin D (morning sunlight). Scurvy – lack of vitamin C (citrus fruits). Night blindness – lack of vitamin A (carrot, spinach, papaya).
To save nutrients: wash vegetables before cutting, cook potatoes with peel, cook cut vegetables at once in just enough water.
Many people — farmers, workers, sellers, cooks — bring food from farm to plate, so we must not waste food.
Important terms
Diet (आहार) – food we eat regularly.
Regional diet – diet based on local crops and climate.
Nutrients (पोषकद्रव्ये) – components of food needed by the body.
Deficiency disease – disease caused by lack of a nutrient.
Millets – small grains like jowar, bajra and ragi.
Key facts
Disease
Lack of
Remedy
Goitre
Iodine
Iodized salt
Rickets
Vitamin D
Morning sunlight
Scurvy
Vitamin C
Citrus fruits
Night blindness
Vitamin A
Carrot, papaya, spinach
5 important questions
Q1. What is a regional diet?
A diet based on the crops grown and the climate of a particular region.
Q2. Name the main nutrients in food.
Carbohydrates, proteins, fats, vitamins, minerals, water and fibre.
Q3. What causes rickets and how can it be prevented?
Lack of vitamin D; sitting in morning sunlight helps.
Q4. Why should vegetables be washed before cutting?
If washed after cutting, nutrients dissolve in water and are lost.
Q5. Why should we not waste food?
Many people like farmers, workers and cooks work hard to bring it to our plate.
Exam tip
Learn the deficiency disease table thoroughly — it is a sure question.
Magnets are used in pumps, generators, ATM cards, MRI machines and speakers. This chapter explains magnetic and non-magnetic substances, poles of a magnet, attraction and repulsion, and the magnetic compass.
Key points
Magnets are used in electric pumps, electric generators, ATM cards (magnetic strip), MRI machines, headphones and speakers.
Substances attracted by a magnet are magnetic: iron, cobalt and nickel.
Substances not attracted are non-magnetic: glass, plastic, wood.
The ends of a magnet where its force is greatest are its poles. Every magnet has two poles: north and south.
The two poles of a magnet can never be separated; breaking a magnet gives two smaller magnets.
A freely suspended magnet always comes to rest in the north–south direction.
The end pointing north is the north pole; the end pointing south is the south pole.
Like poles repel each other; unlike poles attract each other.
Magnets of many shapes are made artificially: bar, horseshoe, ring, U-shaped.
A magnetic compass finds directions because its needle (a magnet) settles north–south.
Important terms
Magnetic substance – attracted by a magnet.
Pole (ध्रुव) – end of a magnet with greatest force.
A push or a pull on an object is a force. This chapter explains different kinds of forces — muscular, mechanical, gravitational, magnetic, frictional and electrostatic — balanced and unbalanced forces, and pressure, including atmospheric pressure.
Key points
The effort to push or pull an object is called force.
Muscular force: applied using our muscles (lifting a bag).
Mechanical force: applied by a machine (a crane lifting load).
Gravitational force: the earth pulls all objects towards itself; that is why things fall down.
Magnetic force: exerted by a magnet.
Frictional force opposes motion and reduces speed (a rolling ball stops).
Rubbing plastic, rubber or ebonite produces static charges; the force due to them is electrostatic force (a rubbed comb attracts paper bits).
Two equal forces acting in opposite directions keep an object at rest: balanced forces.
Unequal forces are unbalanced forces; the object moves in the direction of the bigger force (tug of war).
Force acting on a unit area is pressure. For the same force, smaller area gives more pressure (a sharp knife cuts easily).
Air exerts atmospheric pressure. Differences in air pressure cause winds and storms.
Important terms
Force (बल) – a push or a pull.
Friction (घर्षण) – force that opposes motion.
Balanced forces – equal and opposite forces.
Pressure (दाब) – force acting on unit area.
Atmospheric pressure – pressure exerted by air.
Formulas
Pressure = Force ÷ Area
SI unit of force: newton (N). SI unit of pressure: pascal (Pa) = N/m².
5 important questions
Q1. What is force? Give two examples.
A push or a pull on an object. Examples: pushing a door, pulling a bucket from a well.
Q2. Why does a ball rolling on the ground slowly stop?
Friction between the ball and the ground opposes its motion.
Q3. What are balanced forces?
Two equal forces acting on an object in opposite directions, so the object stays at rest.
Q4. Why is a knife sharpened?
A sharp edge has a small area, so the same force gives more pressure and it cuts easily.
Q5. A force of 100 N acts on an area of 2 m². Find the pressure.
Pressure = 100 ÷ 2 = 50 N/m² (50 Pa).
Exam tip
Give one daily-life example for every type of force.
An object is in motion when its position keeps changing. This chapter explains how motion depends on the observer and reference point, and describes linear, circular, oscillatory and random motion.
Key points
When the position of an object changes with time, it is in motion. If it does not change, the object is at rest.
Whether something is moving depends on the observer and the reference point.
A passenger in a bus sees other passengers as not moving; a person outside sees them moving with the bus.
Linear motion: along a straight line (a car on a straight road, a falling stone).
Non-linear motion: not in a straight line.
Circular motion: along a circle (blades of a fan, a stone tied to a string and whirled).
Oscillatory motion: to and fro about a fixed point (a swing, a pendulum).
Random motion: no fixed direction (a butterfly, a football player, dust particles).
Sometimes many types of motion happen together (a bicycle wheel turns in a circle while the bicycle moves in a line).
Important terms
Motion (गती) – change in position with time.
Rest – no change in position.
Reference point – a fixed point used to judge motion.
Oscillatory motion – to-and-fro motion.
Random motion – motion with no fixed path.
Key facts
Type of motion
Example
Linear
Train on straight track
Circular
Ceiling fan blades
Oscillatory
Swing, pendulum
Random
Flying housefly
5 important questions
Q1. When is an object said to be in motion?
When its position keeps changing with time.
Q2. Why does a passenger in a bus think other passengers are not moving?
Compared to him (his reference point), their position is not changing.
Q3. What is oscillatory motion? Give an example.
To-and-fro motion about a point, like a swing.
Q4. Give two examples of random motion.
A flying butterfly and a footballer during a match.
Q5. Which types of motion does a moving bicycle wheel show?
Circular motion (turning) and linear motion (moving forward).
Exam tip
Practise classifying everyday examples into the four types of motion.
Soil, water, sea, sunlight, air, forests and fossil fuels are gifts of nature called natural resources. This chapter explains their uses, the three types of natural resources and why we must use them carefully.
Key points
Natural resources include soil, water, sea, sun, air, forests and fossil fuels.
Black soil is very fertile and good for farming.
Water sources: rain, groundwater, springs, streams, ponds, rivers and seas. Rainwater should be stored.
The sea gives food (fish), minerals and materials for medicines.
Sunlight gives solar energy; wind gives wind energy.
Forests give food, medicines, gum, wood and many useful things.
Fossil fuels are of three main kinds: coal, petrol/diesel and natural gas.
Renewable resources are produced again and again by nature (water, soil).
Non-renewable resources are limited and take thousands of years to form again (coal, petrol, natural gas). They must be used sparingly.
Sustainable (never-ending) resources like sunlight, wind and sea waves are always available.
Important terms
Natural resources (नैसर्गिक संसाधने) – useful things given by nature.
Renewable – formed again and again by nature.
Non-renewable – limited, takes very long to form again.
Sustainable resource – one that is always available (sun, wind).
Fossil fuel – fuel formed from remains of ancient living things.
Key facts
Type
Examples
Renewable
Water, soil
Non-renewable
Coal, petrol, natural gas
Sustainable
Sunlight, wind, sea waves
5 important questions
Q1. What are the three types of natural resources?
Renewable, non-renewable and sustainable.
Q2. Why should fossil fuels be used sparingly?
They are limited and take thousands of years to form again.
Q3. Why is solar energy called inexhaustible?
Sunlight is always available in nature and never gets used up.
Q4. What do we get from the sea?
Food like fish, minerals and materials for medicines.
Q5. Why is it necessary to store rainwater?
Rainwater can be used later and it helps raise groundwater levels.