Chapter 3
Food And Health
E. Answer the following questions.
Why is a balanced diet required for good health?
Ans - A balanced diet provides all essential nutrients in the right amount, which helps in body growth, energy, and protection from diseases.
Why is water essential for our body?
Ans - Water is essential because it helps in digestion, regulates body temperature, removes waste through urine and sweat, and transports nutrients.
Why should one take protein in his/her diet daily?
Ans - Proteins help in body growth, repair of tissues, and formation of new cells, which is especially important for growing children.
Name different nutrients present in food. Describe at least one function of each.
Carbohydrates – Give energy
Proteins – Help in growth and repair
Fats – Provide energy and help absorb vitamins
Vitamins – Protect from diseases (e.g., Vitamin C prevents scurvy)
Minerals – Help in body functions like bone strength (e.g., Calcium)
Water – Helps in digestion and maintaining body temperature
Roughage – Aids digestion and prevents constipation
Vitamin D is also called the sunshine vitamin. Give reason.
Ans - Vitamin D is called the sunshine vitamin because our body produces it when the skin is exposed to sunlight.
Science and Sense
Why should we not eat cut fruits and uncovered food?
Ans - We should not eat cut fruits and uncovered food because cut fruits and uncovered food can be contaminated by dust, flies, and germs, which may cause food poisoning or diseases.
Observe and Explore – Home Activity
Day-wise Observation Table:
Days
Change in Colour
Change in Smell
1
No visible change
Normal smell
2
Slight spots appear
Slightly sour smell
3
Green/white patches
Stronger unpleasant smell
4
Patches become larger
Foul smell
5
Mold fully covers it
Very foul smell
6
Bread fully rotten
Extremely bad smell
Chapter 4
Pollination
E. Answer the following questions.
The different parts of a plant are root, stem, leaves, flowers, fruits, and seeds.
2. What is androecium?
Androecium is the male reproductive part of a flower. It includes anther and filament.
3. Name the parts of female reproductive organ of a flower.
Stigma, style, and ovary (together called pistil or gynoecium) are the parts of female reproductive organ of a flower.
4. How do the colours and fragrance of a flower help in reproduction?
The bright colours and sweet fragrance attract insects and other pollinators, which help in transferring pollen from one flower to another, aiding in pollination.
5. Describe the various ways of pollination.
- Self-pollination – Pollen is transferred from anther to stigma of the same flower or same plant.
- Cross-pollination – Pollen is transferred from the anther of one flower to the stigma of a flower on a different plant of the same species.
- Agents like wind, insects, birds, and water help in pollination.
6. What are pollinators? Give any three examples.
Pollinators are agents that help in the transfer of pollen from anther to stigma.
Examples: Bees, butterflies, and wind
Science and Sense
Q no 1. How does wind help in reproduction in plants?
Wind carries the pollen grains from the anther of one flower and helps them land on the stigma of another flower, allowing fertilization and reproduction.
Q no. 2 “Rose is a perfect flower.” What is the meaning of being a perfect flower?
A perfect flower has both male (stamen) and female (pistil) reproductive organs, allowing it to reproduce on its own.
E. Give one word for the following:
Reproduction of new plant by fertilization – Sexual reproduction
Agents that help in pollination – Pollinators
Growing plants from different parts such as root, stem or leaf – Vegetative reproduction
A plant that grows from its leaves – Bryophyllum
The buds of potatoes – Eyes
F. Answer the following questions.
What is reproduction? What are its different types?
Reproduction is the process by which plants produce new individuals.
It is of two types:
Sexual reproduction
Asexual reproduction (e.g., vegetative propagation)
Describe the process of sexual reproduction in plants.
In sexual reproduction, pollen from the anther is transferred to the stigma (pollination). It moves down the style to the ovary, where it fertilizes the ovule. The fertilized ovule becomes a seed and the ovary turns into a fruit.
What are the necessary conditions for seeds to germinate?
Seeds need air, water, warmth, and space to germinate.
What is germination?
Germination is the process by which a seed develops into a new seedling or baby plant under suitable conditions.
Describe any three methods of vegetative reproduction in brief.
By stem (e.g., rose) – New plants grow from stem cuttings.
By leaves (e.g., bryophyllum) – New plantlets grow from leaf edges.
By roots (e.g., carrot) – Roots store food and grow into new plants.
What is seed dispersal? Name the agents of seed dispersal.
Seed dispersal is the process of scattering seeds away from the parent plant.
Agents: Wind, water, animals, explosion
Science and Sense
Why is the dispersal very important?
Dispersal is important because it provides space, air, water, and sunlight for each seedling to grow properly without overcrowding.
Why do plants need to reproduce?
Plants need to reproduce to ensure the continuity of their species.
Learn with Fun
A. Crossword Puzzle
Down:
A plant that reproduces through stem cutting – Rose
The part of female reproductive organ of flower that changes into fruit – Ovary
Scattering of seeds away from mother plant – Dispersal
Male part of a flower – Stamen
Across:
5. A sac-like part of flower that contains pollens – Anther
6. An agent of plant pollination and seed dispersal – Wind (or Insect)
7. The female reproductive part of flower – Pistil
8. The dust-like particles in flowers that transfer through insects, birds, wind etc. – Pollen
E. Answer the following questions.
Define matter.
Matter is anything that occupies space and has mass.
What are soluble substances?
Soluble substances are those that dissolve in a liquid (usually water), like salt or sugar.
Name the main gases present in air.
Nitrogen
Oxygen
Carbon dioxide
Argon
Name three states of matter. Compare the properties of three states of matter.
Property
Solid
Liquid
Gas
Shape
Definite
No definite shape
No definite shape
Volume
Definite
Definite
No definite volume
Particle Arrangement
Closely packed
Less tightly packed
Very loosely packed
Compressibility
Cannot be compressed
Slightly compressible
Easily compressible
Does the volume of a liquid change if a solid gets dissolved in it? If no, why?
No, the volume doesn’t change much because the solid particles settle into the spaces between the liquid particles.
What is a solution?
A solution is a uniform mixture of two or more substances. It is formed when a solute dissolves in a solvent.
What is the composition of air?
Air is composed mainly of:
78% Nitrogen
21% Oxygen
1% other gases (like carbon dioxide, argon, etc.)
How are land breeze and sea breeze caused?
Sea breeze occurs during the day: land heats up faster than water; warm air over land rises and cool air from the sea moves in to take its place.
Land breeze occurs during the night: land cools faster than sea; warm air over the sea rises and cool air from the land moves to the sea.
Science and Sense
Why can’t we press a solid?
Because the particles of a solid are closely packed, leaving no room for compression.
Why can gases be squeezed into a smaller space?
Because the particles in gases are far apart, allowing them to be compressed easily.
Why are the ventilators in houses provided higher up in the walls, whereas windows are made lower down?
Because warm air rises, and ventilators allow the hot air to escape, while cooler air enters from lower windows.
Learn with Fun
A. Unscramble the words:
HILQUD → LIQUID
EINSMTTIDEAON → SEDIMENTATION
ENDACAIOTTN → DECANTATION
TSOM R → STORM
NNTOGEIR → NITROGEN
B. Use the hints to complete the words:
It occurs during day time from sea to land.
S E A B R E E Z E
These are provided above window to act as passage for hot air to move out.
V E N T I L A T O R
It is a technique to separate an insoluble solid from a liquid.
F I L T R A T I O N
A gas present in air that is used to inhale.
O X Y G E N
Chapter 7Interdependence in living beings: Plants and AnimalsE. Answer the following questions.
What is environment?
Environment is everything that surrounds us—living (biotic) and non-living (abiotic) components.
What are producers?
Producers are organisms (like green plants) that can make their own food using sunlight, air, and water through photosynthesis.
What are consumers?
Consumers are organisms that depend on other organisms for their food.
Give examples of biotic and abiotic components.
Biotic: Plants, animals, humans, fungi
Abiotic: Air, water, soil, sunlight
What is a food chain? Give an example of a food chain in a forest.
A food chain shows how energy is passed from one organism to another.
Example: Grass → Deer → Tiger
What is the importance of decomposers in a food chain?
Decomposers break down dead plants and animals into simpler substances, returning nutrients to the soil. This helps in maintaining the balance of nature.
How are living organisms interdependent on each other?
Plants provide food and oxygen.
Animals depend on plants and also help in pollination, seed dispersal.
Humans depend on plants and animals for food.
All living beings need one another directly or indirectly to survive.
What are the various causes of imbalance in nature?
Deforestation
Pollution
Excessive hunting
Burning fossil fuels
Overuse of natural resources
Science and Sense
How are trees helpful in maintaining ecological balance?
Trees provide food and shelter to many animals.
They produce oxygen and absorb carbon dioxide.
They help in rainfall and keep the environment cool and clean.
What happens if all tigers are removed from the earth?
The population of herbivores (like deer) will increase rapidly, leading to overgrazing and destruction of plant life, disturbing the ecological balance.
Learn with Fun – Crossword
Across:
FLORA – Plant species of biosphere
BIOSPHERE – Environment of living organisms
CONSUMERS – Organisms that consume the food made by producers
ENVIRONMENT – The surroundings around us
PLANTS – Organisms that make their own food
Down:
ABIOTIC – Component of environment comprising all the non-living things
METHANE – A greenhouse gas
BIOTIC – Living component of environment
DECOMPOSERS – Organisms that help to enrich soil by recycling nutrients
Chapter 8Sound and NoiseE. Give two examples of each
Soft sound
Chirping of birds
Flowing water
Noise
Honking of vehicles
Loudspeakers
Health problems caused due to noise
Headache
Hearing loss
Sounds of intensity less than 80 dB
Human conversation
Television at low volume
F. Answer the following questions
How are we able to produce sounds?
We produce sound when our vocal cords vibrate as air passes through them during speaking or shouting.
What are pleasant and unpleasant sounds?
Pleasant sounds are those we enjoy (e.g., music, birdsong).
Unpleasant sounds or noise are loud, harsh, and disturbing (e.g., traffic noise).
What are warning sounds?
Warning sounds alert us to danger.
Examples: fire alarms, sirens, ambulance horns.
What are the harmful effects of loud noise?
Headache
Hearing loss
High blood pressure (hypertension)
Irritation and lack of concentration
What are the different ways of reducing noise pollution?
Planting trees
Using soundproofing in buildings
Honking only when necessary
Reducing volume of music systems and TVs
Making laws against use of loudspeakers at odd hours
Science and Sense
“Honking of vehicles is also a warning sound.” Do you agree with this? Give reason.
Yes, I agree. Honking is used to alert people and other vehicles that a car is coming or needs way to move forward.
Reduction in noise pollution is possible through contribution of every individual. Do you agree?
Yes, because each home can produce noise through TV, music systems, etc. Controlling volume at home is our personal responsibility, and everyone’s effort can reduce overall noise.
B. Unscramble the words
IRNSE → SIREN
ECIBDLE → DECIBEL
SWEITHL → WHISTLE
ESOIN → NOISE
PRTYHESE NIO → HYPERTENSION
Chapter 9Work and Energy1. Give three examples of objects possessing potential energy.
A stretched rubber band
Water stored in a dam
A book kept on a shelf
2. Write any two uses of heat energy.
It is used for cooking food.
It is used for drying clothes and warming rooms.
3. Write any two uses of electricity.
It is used for lighting bulbs, fans, and tube lights.
It is used for running household appliances like refrigerators, televisions, and washing machines.
4. Rohan is pushing a wall from one hour but wall does not move even a centimetre. Has Rohan done any work? Give reason.
Answer: No, Rohan has not done any work because there is no displacement of the wall.
5. When we supply heat to a tumbler, it becomes hot but after some time it becomes cool as it was in the beginning. If energy can neither be created nor destroyed, then where does the heat energy that the tumbler gained go?
Answer: The heat energy gained by the tumbler is transferred to the surrounding air, which becomes warm and rises upward.
Chapter 10Light and ShadowsA. Choose the correct answer.
Which of the following is a luminous object?
✅ (a) Firefly
Frosted glass is a / an
✅ (c) Translucent object
Which of the following does not form shadow?
✅ (c) Glass sheet
Shadow of the sun is shortest at which of the following time?
✅ (b) 12:00 noon
How many complete rotations are taken by Earth during 1 revolution around the sun?
✅ (c) 365
B. Fill in the blanks with the help of words given in the box.
(light, decreases, sun, translucent, lunar)
The sun is the main source of energy on earth.
Light does not need medium to travel.
Wax paper is an example of translucent object.
The size of shadow decreases as the object is moved closer to the light source.
Lunar eclipse occurs when Earth comes in between Sun and Moon.
C. Tick (✔) the correct statements and cross (✖) the wrong ones.
Candle is an artificial source of light. ✔
The shadow formed in the dim light is faint as compared to the shadow formed in the bright light. ✔
The rotation of earth causes seasons, day and night. ✖ (Rotation causes day and night; revolution causes seasons.)
The longest and largest shadow of an object is formed at night. ✖ (No shadow at night — no light source.)
The shadow of a bird flying high in the sky does not form on the ground. ✔
D. Match the column.
Column A
Column B
Firefly
Natural source of light
Time taken by earth in 1 revolution around sun
365 days 6 hours (approximately)
Time taken by earth to rotate on its axis
24 hours (approximately)
Tubelight
Artificial source of light
Moon
Natural non-luminous object
E. Give two examples of each:
Type
Examples
Luminous objects
Sun, Candle
Non-luminous objects
Moon, Chair
Opaque objects
Book, Wall
Transparent objects
Glass, Water
Translucent objects
Frosted glass, Butter paper
F. Answer the following questions:
1. What are non-luminous objects?
Objects that do not produce their own light are called non-luminous objects.
Example: Moon, table.
2. Differentiate between artificial and natural sources of light.
Natural Sources
Artificial Sources
Produced by nature
Made by humans
Examples: Sun, firefly
Examples: Bulb, candle
3. How is a shadow formed?
A shadow is formed when an opaque object blocks the path of light falling on it.
4. What are the various conditions for the formation of a shadow?
There must be a source of light.
There must be an opaque object.
There must be a screen on which shadow can form.
5. What happens to shadow when the source of light is moved closer and away from the object?
When the source of light is closer, the shadow becomes bigger.
When the source of light is farther, the shadow becomes smaller.
6. What are eclipses?
Eclipses are natural phenomena that occur when one celestial body comes in between another and the Sun, blocking its light.
7. Explain the formation of day and night on the Earth.
The rotation of the Earth on its axis causes day and night.
The part facing the Sun experiences day, while the other part has night.
8. Define penumbra and umbra region.
Umbra: The darkest part of the shadow where light is completely blocked.
Penumbra: The lighter part of the shadow where light is partially blocked.
9. How does a lunar eclipse occur?
A lunar eclipse occurs when the Earth comes between the Sun and the Moon, blocking sunlight from reaching the Moon.
10. Describe the formation of a solar eclipse.
A solar eclipse occurs when the Moon comes between the Sun and the Earth, blocking sunlight from reaching the Earth.
(Science and Sense):
1. Why is the shadow of a plane flying high in the sky is not formed on the ground?
The shadow of a plane flying high in the sky is not formed because the ground is too far from the object plane, so light rays spread and no clear shadow forms.
2. The sun cannot form shadow on Earth and Moon. Why?
The Sun cannot form shadow on Earth because the Sun itself is a source of light.
(For a shadow to form, light must fall on an opaque object — not be the source itself.)
A. Unscramble the letters:
Scrambled Word
Correct Word
Clue
PAEOQU
Opaque
Does not allow light to pass
NPARRTASETN
Transparent
Allows light to pass completely
TAOROTIN
Rotation
Spinning of Earth on its axis
EVTIOROLUN
Revolution
Movement of Earth around the Sun
PSEECLI
Eclipse
Blocking of light between heavenly bodies
Chapter 11Simple MachinesA. Choose the correct answer
A stapler is an example of a
✅ (b) second-class lever
A flyover uses the principle of an
✅ (c) inclined plane
A wheel and axle is used in a / an
✅ (b) flagpole
An inclined plane wound around a rod is called
✅ (b) screw
The simple machine used to draw water from a well is a
✅ (c) pulley
The position of the load in a second-class lever is
✅ between the fulcrum and the effort
An example of a third-class lever is a
✅ (c) fishing rod
Wheels with teeth are called
✅ (b) gears
B. Fill in the blanks
(wheel, force, inclined, easy, screw)
Inclined planes are also called ramps.
A simple machine makes our work easy.
The force that we apply on the lever is called effort.
A screw is an inclined plane that goes round and round a rod.
A wheel becomes a machine when it is combined with an axle.
C. Tick (✔) the correct statements and cross (✖) the wrong ones
All simple machines increase force. ✖
A pulley changes the direction of force. ✔
A car is a simple machine. ✖ (It’s a complex machine made of many simple machines.)
It is easier to push up a load on a steep slope. ✖ (Easier on a gentle slope.)
A wheel is a simple machine. ✔
In our body, bones act as levers. ✔
D. Match the column
Column A
Column B
1. First-class lever
(c) See-saw
2. Second-class lever
(a) Bottle opener
3. Third-class lever
(e) Fishing rod
4. Inclined plane
(b) Ramp
5. Pulley
(d) Flag pole
E. Answer the following questions
1. What makes our work easier and faster?
Simple machines make our work easier and faster by either changing the direction of force or increasing the applied force.
2. What do you understand by load, fulcrum and effort?
Load: The object to be moved or lifted.
Fulcrum: The fixed point on which a lever turns.
Effort: The force applied to move the load.
3. How is a first-class lever different from a second and third-class lever?
Type
Position of Fulcrum, Load & Effort
Example
First-class lever
Fulcrum is between load and effort
See-saw
Second-class lever
Load is between fulcrum and effort
Wheelbarrow
Third-class lever
Effort is between fulcrum and load
Fishing rod
4. Give any two examples of wedge and inclined plane.
Wedge: Knife, Axe
Inclined Plane: Ramp, Slide
5. Describe any two examples where body parts act as levers.
Neck: Acts as a first-class lever when we lift our head.
Arm: Acts as a third-class lever when we lift an object using our hand.
6. What is a wedge? On which principle does it work?
A wedge is a simple machine made of two inclined planes joined together.
It works on the principle of an inclined plane and is used to split or cut objects.
7. Give an example of each of the simple machines that you use in your daily life.
Simple Machine
Example
Lever
Scissors
Inclined Plane
Ramp
Pulley
Flagpole
Wheel & Axle
Door knob
Screw
Jar lid
Wedge
Knife
8. Why is a screw more useful than a nail?
A screw holds materials together more tightly and securely than a nail because of its spiral threads, which increase friction and prevent loosening.
Science and Sense
1. In a wheel and axle, if the wheel is triangular or rectangular in shape, would it turn around easily?
If the wheel were triangular or rectangular, it would not roll easily due to uneven surfaces.
Learn with Fun
A. Unscramble the words
Clue
Scrambled Word
Answer
Cutting paper with scissors
ELREV
LEVER
A ramp used to carry patients in wheelchairs
NDENILCIEAPNL
INCLINED PLANE
A razor used for shaving
EDEGW
WEDGE
A stage curtain makes use of it
LYUPLE
PULLEY
A crane used to lift heavy objects
WCSER
SCREW
B. Crossword Puzzle
Across
2. Pulley – Flagpoles, clotheslines, and curtain strings use it.
3. Fulcrum – The point on which a lever turns.
5. Knife – An example of wedge.
9. Thread – Raised line on a screw.
10. Load – The weight on which force is applied.
Down
Ramp – Inclined plane near a staircase.
Lever – A bar free to move about a fixed point.
Effort – The force applied on a lever.
Gear – A wheel with teeth.
See-saw – Common example of first-class lever.
Chapter 12
Cleanliness and Hygiene
A. Choose the correct answer
(d) All of these
(c) Get up late in the morning
(b) Skin diseases
(b) Cholera
(a) Vegetable peel
B. Fill in the blanks
Healthy food habits keep us healthy.
We should not eat food from roadside vendors.
Malaria is spread due to a mosquito that breeds in dirty water.
Biodegradable garbage can be converted into useful natural products like compost.
We should use cloth bags to reduce non-degradable waste.
C. Tick (✓) the correct statements and cross (✗) the wrong ones
We should eat fruit chats from vendors which cooks dirty. — ✗
We should wear clean clothes every day. — ✓
Heaps of garbage are the homes of germs. — ✓
Eating balanced diet can cause food poisoning. — ✗
We should reuse plastic jars and bottles for as long as possible. — ✓
D. Match the columns
Column A
Column B
1. Plastic bags
(c) Harmful for environment
2. Germs of dengue
(a) Mosquito bite
3. Germs of diarrhoea
(b) Enters through dirty water
4. Brush your teeth daily
(d) Good habit
5. Do not take bath daily
(e) Bad habit
E. Give two examples
Diseases caused by contaminated water: Cholera, Typhoid
Substances formed by degradable garbage through decomposition: Compost, Manure
Degradable garbage: Vegetable peels, Paper
Non-degradable garbage: Plastic bottles, Metallic cans
F. Answer the following questions
1. Write any three healthy habits.
Brushing teeth twice a day
Taking bath daily
Eating fresh and clean food
2. How do germs enter our body?
Germs enter our body through dirty food, contaminated water, unclean hands, or insect bites.
3. How many times should we brush our teeth?
We should brush our teeth twice a day — in the morning and before going to bed.
4. How does keeping clean protect us from disease?
Keeping clean removes germs and dirt, preventing infections and diseases.
5. What are the different diseases caused due to lack of personal hygiene?
Cholera, Typhoid, Jaundice, Malaria, and Skin diseases.
6. What is degradable garbage?
Degradable garbage is waste that can decay naturally and change into compost, like vegetable peels and paper.
7. Why is non-degradable waste more harmful than degradable waste?
Non-degradable waste cannot be broken down naturally, so it pollutes soil, water, and air for a long time.
8. What are the ways to reduce non-degradable waste?
Use cloth or paper bags instead of plastic.
Reuse bottles and containers.
Recycle plastic and metal items.
Science and Sense
Q: The fruit chat vendors sell tasty chats. Fruits are good for health, then why should we avoid eating such things from roadside vendors?
A: Because the fruits may be stale or dirty, and vendors often do not maintain proper hygiene, which can cause diseases.
Q: By using paper or cloth bags, can we reduce the non-degradable waste to zero?
A: No. We can reduce non-degradable waste but not make it zero, because some plastic items are still needed and used.
Learn with Fun
A. Rearrange the jumbled letters
REGSM → GERMS
ERADDGLEB → DEGRADABLE
BREAAG → GARBAGE
YINEHGE → HYGIENE
B. Crossword Answers
Across:
2. Sick
4. Germs
6. Cholera
Down:
Pesticide
Hygiene
