science class -3- 2077 press

Project Work

Observe various plants in your surrounding. Make
different tables to classify the plants into following groups in
your project work copy.
a. Non-flowering and flowering plants (4 each).
b. Annual, biennial and perennial plants (4 each).
c. Terrestrial and aquatic plants (4 each).
d. Summer and winter plants (4 each)
Show the work to your teacher.

Exercise

1. Fill in the blanks with suitable words.

winter seeds perennial nonflowering annual

a. Flowering plants reproduce by .........................

b. Fern and mushroom are ......................... plants.

c. ......................... plants survive for one season only.

d. Mango is a ......................... plant.

e. Radish is grown in ......................... season.

2. Write ‘True’ for the correct sentences and ‘False’ for the
wrong ones.

a. Mustard is a flowering plant.
b. Biennial plants survive for one season only.
c. Perennial plants grow for many years.

Blooming Science, Health and Physical Education Book 3 51

d. Summer plants can be grown in winter also
in a green house.

e. Rayo sag is usually found in winter season.
3. Classify the following plants as annual and perennial plants.

Apple pumpkin wheat grapes
orange
pea litchi rayo bean

coconut mango mustard

4. Write down the name of any three:

a. Flowering plants

.............................. .............................. ..............................

b. Non-flowering plants

.............................. .............................. ..............................

c. Annual plants

.............................. .............................. ..............................

d. Biennial plants

.............................. .............................. ..............................

e. Perennial plants

.............................. .............................. ..............................

f. Terrestrial plants

.............................. .............................. ..............................

g. Aquatic plants

.............................. .............................. ..............................

52 Blooming Science, Health and Physical Education Book 3

h. Winter plants
.............................. .............................. ..............................
i. Summer plants
.............................. .............................. ..............................
5. Draw a diagram of a mustard plant. Write down about it
based on the following:
a. Flowering/ Non-flowering
b. Terrestrial/ aquatic
c. Annual / biennial / perennial
d. Winter/ summer

Blooming Science, Health and Physical Education Book 3 53

Lesson Advantages of Plants
and Animals
6

Learning outcomes
At the end of this lesson, the students will be able to:
 tell the advantages of animals and plants to human beings.

 identify the useful things (food, clothes and others) obtained from
animals and plants.

Boost Up Fruits

Match the following.

Carbohydrates

Proteins Animals

Vitamins and minerals Bee

Wool Cereals

Honey Pulses

We live in this nature. Food, shelter
and clothing are our basic needs. We
depend upon animals and plants to
fullfill our basic needs. We get our foods

54 Blooming Science, Health and Physical Education Book 3

from plants and animals. We get fibres to make our clothes
from plants and animals. We make our house by using various
things obtained from the plants. Animals and plants are useful
to us in many other ways also. We can not survive without
animals and plants.

Advantages of plants

We use plants for various purposes. Our food basically
depends upon plants. We use plants for fibres, medicines and
constructions etc. Some uses of plants are explained in brief
here.

A. Plants as food

We need food to live. We need food to get energy to work
and play. Food is required for the growth and development of
our body. Most of our food comes from plants. Plants prepare
their food by themselves. All the food prepared by plants are
not used by them and this food is stored in different parts. We
eat these parts as our food.

1. Cereals

We eat the seeds of various plants as energy giving food.
Most of our food are made by cereals. Rice, maize, barley,
millet, buckwheat, etc. are some examples of cereals. These
contain carbohydrate and provides energy to us.

Blooming Science, Health and Physical Education Book 3 55

2. Pulses

We eat the seeds of various plants like pea, gram, beans,
kideny beans (Rajma), long beans, red lentil (musuro), rahar,
etc. as pulses. These are rich in proteins and helps for the
growth and development of our body.

3. Vegetables

We get vegetables from different parts of plants. We eat
roots, stem, leaves and flowers of different plants as vegetables.
Vegetables are the sources of vitamin and minerals which
makes our body strong.

i. Roots as vegetables

We eat roots of carrot, turnip, radish and beetroot as
vegetables and salads as well.

56 Blooming Science, Health and Physical Education Book 3

ii. Stem as vegetables

We eat potato, onion, garlic and ginger as vegetables
and spices as well.

iii. Leaves as vegetables

We eat leaves of cabbage, spinach, lettuce, broad leaf
mustard (rayo), coriander, pumpkin vine shoot, cress
(chamsur), fenugreek (methi), etc. as vegetables.

iv. Flowers as vegetables

We eat flowers of cauliflower and broccoli as vegetables.
They provide proteins also.

Blooming Science, Health and Physical Education Book 3 57

v. Fruits as vegetables

We eat fruits of some plants like tomato, brinjal,
pumpkin, chilli, bottle gourd, long gourd, bitter gourd,
etc. as vegetables.

4. Fruits

We eat fruits of some plants. They are juicy and delicious
to eat. The fruits provide us vitamins and minerals, which are
helpful in keeping our body strong and protecting us from
various diseases.

B. Plants as medicines

Some plants like tulsi, mint, neem, babari, harro, barro,
amala, rajbrikshya, padamchal, sarpagandha, alloevera, etc.
are are used as medicines.

58 Blooming Science, Health and Physical Education Book 3

C. Fibres from plants

Cotton fibres are obtained from cotton plants which are
used in clothing. Similarly, fibres of plants like jute, coconut,
hemp, etc. are used to make clothes, ropes, nets, sacks, carpets,
doormats, etc.

D. Other uses of plants

Plants are used for fire wood and timber also. We make
furnitures, doors, windows, etc. by using the plants. Some
plants are also used for tea grains, coffee, rubber, oil, perfumes
and gum.

Advantages of Animals

Various animals are useful to us in many fields. Because
of their uses, some animals are kept at our homes as domestic
animals and pet animals. We get food and fibres from animals.
Some advantages of animals are discussed here.

A. Food from animals

We get our food from animals as well. We obtain milk and
milk products from cows, buffaloes, goats and yaks. We eat the
eggs of ducks and hens. We also eat meat of some animals like

Blooming Science, Health and Physical Education Book 3 59

hen, duck, fish, goat, pigs and buffaloes. We get honey from
honeybees. Various food materials obtained from animals are
rich in fat, proteins, vitamins and minerals.

B. Fibres from animals

We get fibres and leather from animals. Animals like sheep,
rabbit and himalayan goat gives wool. Silkworm gives silkfibre.
We also use skin of some animals as leather for making belts,
shoes, jackets and other things.

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C. Other uses of animals

Besides food and fibres, animals are useful to us in many
other ways. We use some animals like mule, horse, yak, sheep
and camel for transportation to carry the loads. Some animals
like oxe and buffaloes are used by the farmers to plough the
fields and to pull the carts. Animal’s excreta is used as fuel and
manure. We keep dogs and cats for security and entertainment
as pet animals.

Key words

Construction – the act of constructing/making.
material produced from the skin of animal.
Leather – liquid that gives a pleasant smell.
source that gives energy by burning.
Perfume – excreted matter as urine, feces, etc.

Fuel –

Excreta –

Main Points to Remember

 Animals and plants are very advantageous to us.
 We get foods, fibres and medicines from plants.
 Plants are useful to us as they give us timber, wood, tea, coffee, perfumes, rubber

and gum also.
 We get food, fibres and leathers from animals.
 We also use animals for transportation and farming as well. Similarly, excreta of

animals are used as manure and fuel.

Blooming Science, Health and Physical Education Book 3 61

Project Work

Observe any ten plants and ten animals in your
surroundings. Make and complete the table as given below
in your project work copy and show it to your teacher.

S.No Name of plants Edible parts S.No Name of animals Uses

1. Wheat Seed 1. Hen egg

2. 2.

3. 3

4. 4.

5. 5

6. 6.

7. 7.

8. 8.

9. 9.

10 10.

Exercise

1. Fill in the blanks with suitable words.
fibres proteins leaves carbohydrates fruits

a. Cereals are the sources of ...........................
b. Pulses are the source of ...........................
c. We use the ...................... of leafy plants as vegetables.

62 Blooming Science, Health and Physical Education Book 3

d. ........................... are the main sources of vitamins and
minerals.

e. Plant ........................... are used to make clothes.

2. Write ‘True’ for the correct sentences and ‘False’ for the
wrong ones.

a. We use grains of rice, wheat and barley as
our food.

b. We get food from leaves of soyabean.
c. Tomato, brinjal and pumpkin are the fruits

we eat as vegetables.
d. The skin of animals is used as leather to make

various goods.
e. We get tea and coffee from plants.

3. Match the following:

Silkworm milk

Horse meat

Buffalo pet animal

pig fibre

cat transportation

Blooming Science, Health and Physical Education Book 3 63

4. Name the parts of following plants that can be used as food:

Maize Rajma Carrot Potato

Radish Spinach Lettuce Apple

Brinjal Rayo Onion Tomato

5. Answer the following questions.

a. Write down any three advantages of plants.

.............................................................................................

.............................................................................................

.............................................................................................

b. Write down any three advantages of animals.

.............................................................................................

.............................................................................................

.............................................................................................

c. Write down any three examples of plants that are
used as medicines.

........................... ........................... ...........................

d. Name any two plants whose flowers are eaten as
vegetables.

e. Name any three animals that give us wool.

........................... ...........................

f. Write down the name of any three articles made by
animal’s leather.

........................... ........................... ...........................

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6. Draw and colour the following:
a. A plant with edible root
b. A plant with edible flower.
c. An edible fruit.

Blooming Science, Health and Physical Education Book 3 65

Lesson Our Environment

7

Learning outcomes
At the end of this lesson, the students will be able to:
 identify the causes of environmental pollution .
 tell and apply the ways of keeping the environment clean.

Boost Up

Match the following.

Smoke from vehicles Soil pollution
Air pollution
Defecating near the
water sources

Plastics and bottles Environmental pollution

Deforestation Water pollution

Environment is the place where we live in. It includes all
the living and non living things like animals, plants, air, water,
soil, rocks, etc. It means environment is the surrounding around
us. It should be kept clean in order to live a healthy life. When
all the components of our surroundings remain clean, then our
environment becomes clean and suitable for us to live a healthy
life. The environment becomes dirty when some unwanted
materials are mixed in it. We are mixing various unwanted

66 Blooming Science, Health and Physical Education Book 3

things in our surroundings and making the environment dirty.
By the over use of modern technologies and lack of awareness
about importance of a clean environment, it is made dirty day
by day. A dirty environment is not safe to live. It leads to many
diseases in human beings . So, to live a healthy life, we must
keep our environment clean.

Environmental pollution

Environment is the home for all living organisms. Clean
environment is essential for a healthy life. Different kinds of
human activities are making our environment dirty. Different
kinds of wastes are produced by our house hold activities,
domestic animals, industries and hospitals. We are disposing
these waste materials in the environment. So, we are making
our environment dirty.

The degradation in the quality of the environment is
known as environmental pollution. As mentioned earlier,
environmental pollution is caused by various human activities.
When any component of the environment is made dirty, then it
causes pollution. Mainly three types of environmental pollution
are there. They are, (i) Water pollution (ii) Air pollution and
(iii) Soil pollution.

Mixing of some unwanted materials in the water it causes
water pollution. Mainly, water pollution is caused by mixing
drainage and sewage from cities in the river. People throw
their domestic and industrial wastes in water. In many areas,
people are defecating and urinating in water resource. Water
gets polluted by washing clothes, taking bath and bathing
the animals directly in the water resources. Polluted water
causes various water-borne diseases as well as many other
environmental problems.

Blooming Science, Health and Physical Education Book 3 67

Air pollution is caused by the mixing of unwanted
substances like smokes from vehicles, industries and from other
household activities. It is also caused by the deforestation. We
need air for breathing. When air is polluted, various respiratory
diseases are seen in human beings.

Soil pollution is caused by the mixing of non-degradable
wastes in soil. Such non-degradable wastes are produced in
various household activities, hospitals and industries. The
fertility of soil decreases and leads to the low production of
crops if the soil is polluted.

Causes of environmental pollution

Our environment becomes polluted because of the following
reasons:

1. People are not aware about the importance of a clean
environment. They are not using the toilets properly.
Generally, people defecate everywhere which causes
environmental pollution.

2. Domestic animals are not kept properly. People leave the
domestic animals on the road. They pass dung and urine
here and there. Some animals are taken to the water resources
for bathing, which cause environmental pollution.

3. Improper management of wastes: Many different types
of wastes are produced in various household activities.
Instead of separating these degradable and non-
degradable wastes and managing it properly these are
directly thrown in rivers, lakes or in open places which
causes environmental pollution.

4. Smokes from vehicles, industries and household use
Burning fire wood in kitchen and the vehicles and

68 Blooming Science, Health and Physical Education Book 3

industries produce excess smoke which is mixed in air
and causes pollution.
5. There are no proper ways of draining out dirty water from
houses and drain pipes are directly connected with the
water resources. So, the improper drainage system is also
causing the pollution.
6. Deforestation: The cutting down of trees reduces the
amount of oxygen in the air and the animals may not get
enough oxygen to breathe.

Methods of keeping the environment clean

Some methods that can be applied to make the environment
clean are as follow:
1. We must make the people aware about the importance of

a clean environment and the proper use of toilet, etc.
2. Domestic animals should be kept in a healthy way. Their

shelters should be cleaned properly and their wastes must
be discharged well, so that it can be used as manure.
3. Wemustmangethehouseholdwastesproperly.Degradable
wastes should be converted into compost manure where
as non-degradable wastes should be reused or recycled.

Blooming Science, Health and Physical Education Book 3 69

4. Instead of firewood, we should use alternative sources
of energy like biogas. While using firewood, smokeless
chimneys have to be used in the kitchen. The vehicles must
be maintained properly so that they produce less smoke
and industries with tall chimneys must be established far
from the residential areas.

5. Drainage should be managed properly. Dirty water coming
out of bathroom and kitchen should be drained properly
into a proper place.

6. Plantation of trees helps to keep the air clean. We should
plant trees around our house. Tree plantation programmes
should be conducted in our locality.

70 Blooming Science, Health and Physical Education Book 3

Key words

Component – a constituent / a part

Drainage – a system of drains

Sewage – waste matter that passes through sewers

Defecating – discharging stool from body

Urinating – discharging urine from body

Degradable – capable of being decomposed

Non-degradable – not capable of being decomposed

Vehicles – means of transport like bus, car, etc.

Manure – any natural or artificial substance for
fertilizing the soil

Main Points to Remember

 Environment is the place where we live in. It includes all the living and nonliving
components of the surroundings.

 The degradation in the quality of environment is called environmental pollution.

 There are three types of environmental pollution; water pollution, air pollution
and soil pollution.

 Environmental pollution is caused by;
– Lack of awareness in the people.
– Improper management of domestic animals
– Improper management of wastes.
– Smoke from vehicles and industries.
– Lack of proper drainage system.
– Deforestation.

 The environment can be kept clean by;
– Increasing the awareness of the people.
– Proper management of domestic animals.
– Proper management of wastes.
– Using smoke free chimneys and vehicles
– Proper drainage system.
– Afforestation and forest conservation programmes

Blooming Science, Health and Physical Education Book 3 71

Project Work

1. Arrange a cleaning campaign in your school or in your
locality with the help of your teacher. How do you feel?
Share with your friends and teacher.

2. Observe a nearby water resource from your school with
the help of your teacher. Is the water clean? What are the
causes of pollution of water? How can it be made clean ?
Write down some points and show to your teacher.

Exercise

1. Fill in the blanks with suitable words.
water environment awareness degradable air
a. Clean ...................... is essential for a healthy life.
b. Defecating near the river causes ................... pollution.
c. Burning plastics causes ...................... pollution.
d. We can minimize pollution by increasing public .........
e. ................... wastes must be collected to make manure.

72 Blooming Science, Health and Physical Education Book 3

2. Write ‘True’ for the correct sentences and ‘False’ for the
wrong ones.

a. Dirty environment causes many diseases.

b. Non-degradable waste causes the soil pollution.

c. We have to free domestic animals to keep
our house and surrounding clean.

d. We can defecate in open places.

e. A smoke chulo should be used in kitchen to
reduce smoke.

3. Answer the following questions.
a. What is environment ? Write down any four
components of environment.
..............................................................................................
..............................................................................................
..............................................................................................
..............................................................................................
b. What is environmental pollution?
..............................................................................................
..............................................................................................
..............................................................................................
..............................................................................................

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c. Define the following.
i) Air pollution
.......................................................................................
.......................................................................................
.......................................................................................
.......................................................................................
ii) Water pollution.
.......................................................................................
.......................................................................................
.......................................................................................
.......................................................................................
d. Write down any three causes of environmental pollution.
..............................................................................................
..............................................................................................
..............................................................................................
..............................................................................................
e. Write down any three ways of keeping the

environment clean.
..............................................................................................
..............................................................................................
..............................................................................................
..............................................................................................

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f. What should we do to the degradable wastes?
..............................................................................................
..............................................................................................
..............................................................................................
..............................................................................................
g. What will happen to us if we lived in a dirty

environment ?
..............................................................................................
..............................................................................................
..............................................................................................
..............................................................................................
4. Sketch a figure of a clean environment and colour it.

Blooming Science, Health and Physical Education Book 3 75

Lesson Types of Matter

8

Learning outcomes
At the end of this lesson, the students will be able to:
 identify and differentiate sinking and floating objects.
 identify and differentiate soluble and insoluble objects.
 identify and differentiate transparent and opaque objects.

Boost Up Gas state

Match the following.

Things that have mass
and occupy space

Water, milk and oil Liquid state

Stone, book and pencil Solid state

Air, smoke and cloud Matters

There are many things around us. They may be natural
or man made, useful or useless, etc. All these substances are
made by materials and occupy space. Anything that occupies
space and has mass (weight) is called matter. Air, water, stone,
smoke, book, milk, etc. are the examples of matters. The matters
are also called as object or substances as they are made by tiny
particles.

76 Blooming Science, Health and Physical Education Book 3

States of matter

Matter exists in three states. They are solid, liquid and gas.

Solid

Solids are mostly hard substances with definite shape and
volume. Stone, book, pencil, chair, table, brick, kitchen utensils,
ball, etc. are the examples of matter found in solid state.

Some solid objects

Liquid

Liquids do not have their own shape but have the definite
volume. Liquids take the shape of the vessels in which they are
kept. Liquids flow from a higher level to a lower level i.e. we
can pour liquid from one vessel to another.

Some liquid objects

Blooming Science, Health and Physical Education Book 3 77

Gas

Gases do not have a definite shape and they do not have a
definite volume. They take the shape of the container in which
they are kept. These are made by light particles and flow in
all directions. Air, smoke, water vapour, hydrogen, helium,
oxygen, etc. are the objects found in gas state. Air is the mixture
of many gases which is found everywhere around us. We can
not see air but we can feel it.

Types of objects

There are different types of objects found in nature. Some
substances are hard whereas some are soft. Some are soluble in
water whereas some are insoluble. Some objects float in water
whereas some sink. Some can pass light whereas some block
the light. Some important types of objects are given here.

Floating and Sinking objects

1. A marble sinking in water 2. A piece of wood floating in
water

78 Blooming Science, Health and Physical Education Book 3

When we put a marble in water, it dips inside the water.
Similarly, when we put a piece of wood in water, it remains on
the surface of water as shown in the figure 1 and 2.

Some objects dip inside water and remain at the bottom
of the vessel. Such objects are called as sinking objects. These
objects are heavier than water. For example coin, marble, iron
nail, stone, etc. sink in water.

When some objects are put in water, they remain on the
surface of water. Such objects are called as floating objects.
These objects are lighter than water. For example feather, paper,
plastic piece, dry wood piece, a leaf, etc. are floating objects.

Activity: 1

Take some objects like coin, marble a wooden piece, stone, cork, plastic piece, feather,
iron nail, etc. Dip these in water kept in a beaker turn by turn. What do you observe?
Write down in your exercise copy. Make a list of objects that sink and that float in
water.

Soluble and Insoluble objects

sugar in sugar dissolves sand in sand does not
water dissolve water
water water

When we mix some sugar in water and stir, it dissolves in
water. Similarly, when we mix some sand in water and stir, it
does not dissolve.

Blooming Science, Health and Physical Education Book 3 79

The objects that dissolve in water are called as soluble
objects. For example salt, sugar, lemon juice, glucose, tang
powder, etc. are soluble objects.

The objects that do not dissolve in water are called as
insoluble objects. For example sand, stone, chalk powder,
wood dust, husk, soil, etc. are insoluble objects.

Activity: 2

Put some objects like salt, sugar, glucose, wood dust, soil, sand, etc. in the water
one by one and stir slowly with a spoon or glass rod. Observe what happens. Which
substances dissolve and which do not dissolve in water? Note down in your copy.
Make a list of some substances that are soluble and that are insoluble in water.

Transparent and Opaque objects

Wow! I can see out with Oh! I can not see out
this plastic with this book

We can see the objects on the opposite side by using a
plastic whereas we can not see the objects on the opposite side
by using a book as shown in the figure above.

Activity: 3

Take a torch light and glow it through a plastic sheet and a book in a dark room.
You can see that the light passes through plastic sheet but does not pass through the
book. You can repeat this activity with glass, clear water, brick, metal sheet, etc. also.
Observe and make a list of these two types of objects.

80 Blooming Science, Health and Physical Education Book 3

The objects through which light can pass are called as
transparent objects. Glass, thin plastic, clean water, etc. are
some transparent objects.

The objects through which light can not pass are called as
opaque objects. Metal sheet, books, thick plastic, wood, etc. are
the examples of opaque objects.

Key words

Mixture – substance made by mixing two or more things
Definite – fixed, exact
Container – anything that can contain something.
Dissolve – to make solution by mixing with liquid / disapper.
Stir – to move one’s hand continuously to mix or dissolve
Tiny – very small

Blooming Science, Health and Physical Education Book 3 81

Main Points to Remember

 Anything that occupies space and has mass is called matter.
 The matters are made by tiny particles and are known as objects or substances.
 The matter exist in three states. They are solid, liquid and gas.
 The matters are of different types; sinking and floating, soluble and insoluble and

transparent and opaque.
 The objects that dip on the bottom of water are sinking objects and the objects

that remain on the surface of water are called floating objects.
 The objects that dissolve in water are called soluble and the objects that do not

dissolve in water are called insoluble objects.
 The objects through which light can pass are called transparent objects and the

objects through which light can not pass are called opaque objects.

Project Work

1. Make a paper boat or a boat by using thermocol sheet
with the help of your parents. Observe whether it floats
on water kept in trough or not. Show it to your teacher.

2. Make a list of any five soluble and insoluble objects each
used in your home. Show it to your teacher.

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Exercise

1. Fill in the blanks with suitable words.
shape mass transparent space lighter mixture

a. The matters have ................... and occupy ....................
b. A liquid substance has definite volume but no

definite ......................
c. Light can pass through ...................... objects.
d. Air is a ...................... of gases.
e. The substances ...................... than water float on it.

2. Write ‘True’ for the correct sentences and ‘False’ for the
wrong ones.
a. The liquid substances flow from a higher
level to a lower level.
b. The substances heavier than water floats on
water.
c. A thin plastic is a transparent object.
d. Soil is not soluble in water.
e. We can see outside from the window fitted
with a glass.

Blooming Science, Health and Physical Education Book 3 83

3. Answer the following questions.

a. What type of substances sink in water? Give any
three examples.

..............................................................................................
..............................................................................................
..............................................................................................
b. Can we find the taste of stone when a soup is made

by boiling stone in water? Why?
..............................................................................................
..............................................................................................
c. Give any three examples of floating objects.
..............................................................................................
..............................................................................................
d. We can not see out from a wooden door, why?
........................... ........................... ...........................
e. Give any three examples of opaque objects.
........................... ........................... ...........................
f. What are transparent objects? Give any three

examples.
..............................................................................................
..............................................................................................
..............................................................................................

84 Blooming Science, Health and Physical Education Book 3

4. Draw the picture of a boat floating on a lake and colour it.

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Lesson Uses of Wind
and Water
9

Learning outcomes
At the end of this lesson, the students will be able to:
 tell the uses of moving air and moving water.

Boost Up

Among the given, write down two uses of moving air
and two uses of moving water.
i) to carry hot balloon
ii) to produce hydroelectricity
iii) to run panighatta.
iv) to separate husk from grains.

Uses of moving air

The surface of our earth is surrounded by a layer of air
called as atmosphere. Air is the mixture of many gases. It is
made by light particles. We can not see air but we can feel it. It
moves freely in the earth’s atmosphere. When we move a book,
a cardboard paper or a small fan infront of our face, we can feel
air. We can feel air while cycling or travelling by a bus also.

The moving air is called as breeze. It is also called as wind.
Generally, we feel comfortable when wind blows in hot summer
days. We can experience blowing wind by keeping a pinwheel
(paper firfire) on our hand with a pin. It rotates in the pin when

86 Blooming Science, Health and Physical Education Book 3

the air moves. When the wind moves fast it can be destructive.
The fast moving wind is called as storm. Sometimes there is
lightening and thundering when there is a storm. Storm causes
the damages such by uprooting the roots, blowing the roofs,
breaking the tree branches, making environment dusty, etc.
The moving air can be very useful to us in following ways:
1. Moving air helps to dry up the clothes.
2. Moving air blows away the dust from our surroundings

and makes the environment clean.
3. In summer days, it dries the sweat and makes our body cool.
4. It is used to carry hot air balloons which is used as a way

of transportation or for entertainment purpose.
5. It is used to play with pin wheel (paper fir fires) and to fly

the kites.
6. It is used to separate husk from the grains.
7. Strong wind is used to run the wind mills which are used

for grinding grains like wheat, maize, millet, etc.
8. Strong wind is also used to generate electricity by rotating

the turbines.

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Uses of moving Water

The earth’s surface is covered by about 75% of water. There
are various sources of water on the surface of earth. The sources
of water are springs, rivers, lakes, seas and oceans. The water
is moving in some sources and remains stationary in some
sources. The living organisms can not survive without water.
We use water for various purposes. The moving (running)
water is very useful to us. In our country, there are many fast
moving rivers. So Nepal is very rich in moving water.
Some important use of moving water are listed below:
1. Moving water can carry various things like dirts, garbage,

etc. and make the environment clean.
2. Moving water can be used for irrigation.
3. A raft is used to travel through moving water. Rafting is a

type of game as well as a means of water transportation.
4. Moving water falling from a certain height is called as

water fall. The waterfalls add to the beauty of nature and
attract the tourists.
5. It is used to run water mills and ‘panighatta’ which are
used for grinding the grains.

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6. In power stations, turbine is rotated by moving water from
certain height which is used to generate hydro electricity.

Hydro electricity is a chief source of energy in our country.

Key words

Breeze – gentle wind

Destructive – causing much damage

Lightening – flash of light seen in the sky

Thundering – sound heard after lightening in the sky

Hot air balloons – huge balloons moving in the sky with the help
of hot air

Husk – dry external covering of seeds

Irrigation – the artificial application of water in cultivable
lands

Power station – the place where electricity is produced.

Raft – Small boat made with rubber and filled with air

Generate – produce

Blooming Science, Health and Physical Education Book 3 89

Main Points to Remember

 The slow moving air is called as breeze and the fast moving air is called as storm.
 The moving air is useful to us in many ways.
 Moving air is useful to dry the clothes and sweat, to fly kites, to separate husk

from grains and in hot air balloon.
 Fast moving air is used to run the windmill and to generate electricity.
 Nepal is very rich in fast moving water as it has many rivers flowing down.
 Moving water is very useful to us. It is used for irrigation and rafting.
 Moving water is used for running ‘Panighatta’ and to generate hydro electricity.

Project Work

1. Make a paper fir fire with the help of your parents/ teacher
and use it.

2. Visit a ‘Panighatta’or a hydro-electricity project if possible
with your parents or teachers. Observe and discuss how
running water works.

3. How is husk separated from grains/rice by farmers in
village or your mother in kitchen? Observe and discuss.

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Exercise

1. Fill in the blanks with suitable words.
wind mill breeze moving air running water rivers
a. The slow moving air is called ...........................
b. ........................... is needed for hot air ballooning.
c. ........................... is needed to run panighatta.
d. In Nepal, there are many fast running ..........................
e. Grains are grinded in ...........................

2. Write ‘True’ for the correct sentences and ‘False’ for the
wrong ones.

a. The storm can cause many damages.
b. Fast moving air can be used to generate

electricity.
c. Only sunlight is required for drying clothes.
d. Water falls from a certain height in

hydroelectricity project to rotate the turbine.
e. Rafting is done in lakes

Blooming Science, Health and Physical Education Book 3 91

3. Answer the following questions.

a. Write down any four uses of moving air.
..............................................................................................
..............................................................................................
..............................................................................................
..............................................................................................
b. Write down any four uses of moving water.
..............................................................................................
..............................................................................................
..............................................................................................
..............................................................................................
c. How is electricity generated in hydro power station?

Explain briefly.
..............................................................................................
..............................................................................................
..............................................................................................
..............................................................................................
d. Nepal has maximum capacity to produce electricity.

Why?
..............................................................................................
..............................................................................................
..............................................................................................
..............................................................................................

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4. Draw the diagram of a pinwheel (paper fir fire) and
colour it.

Blooming Science, Health and Physical Education Book 3 93

Lesson The Weather

10

Learning outcomes
At the end of this lesson, the students will be able to:
 tell the formation of cloud and cause of rainfall.
 explain different types of days like windy days and cold days.
 learn the cause of snow fall.

Boost Up use umbrella

Match the following.
Sun

Winter days dark and cold

Summer days makes the earth hot

Rainy days colder

Cloudy days hotter/warmer

Sometimes we see the sun in the sky and sometimes we
may not see it. We feel hot and cold in different times even
in a single day also. Some days are sunny, some days are
cloudy and some days are rainy. It is because of different
weather conditions. Weather is defined as the condition of
the environment in a day. Weather changes hour to hour and

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day to day. It also changes season to season and year to year.
Weather is affected by sun, wind, cloud and rain.
The main factor that causes change in weather is the sun.
Sun gives us heat and light. Sun does not remain in same position
in the sky as the earth is revolving around it. Sun makes a day
hot. A night is cold because there is no sun. Midday is very
hot compared to the morning and the evening. The sunrays
are slanting in evening and morning whereas falls directly in
midday. The formation of cloud, blowing of wind and rain are
also affected by the presence of sun.

The sun also helps in the formation of clouds. It forms
clouds by evaporating the surface water. When such water
vapour is cooled, it causes rainfall. In this way, sun is the main
factor that conducts the water cycle. When the earth’s surface is
heated due to sun, the air moves resulting in wind. In this way,
the sun is the main factor that causes the change in weather.

Cloud and Rain

Cloud is formed of very small
drops of evaporated water. Cloud
blocks the rays of the sun. A cloudy
day is cold and a cloudy night is
warm as cloud do not let the heat of
the earth to escape out.

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Water is found everywhere on the earth. Because of the
heat of the sun, water vapour is formed. The water vapour rises
up and reaches a cold place. In cold place, it forms the cloud.
Clouds form rain when they cool.
Clouds bring rain. Cloud is a
form of water. During a rainfall,
water drops on the ground. The
rain is the main source of water
on the earth. It also affects the
weather. A rainy day is cold.
Rain water is very important for
the crops.
When cloud forms water, then it leads to rainfall. The water
goes to the river, lakes, seas and oceans. Sunrays evaporate the
water. As the water vapour is lighter than cold air, it reaches
to the cold places in the sky and forms the clouds. When it is
cooled, it is heavy and it drops as rain. The water again mixes
with various sources in the earth. In this way, rain falls again
and again. This process is called as water cycle.

Activity: 1

Boil some water in a kettle. When it starts giving vapour, put a cold steel plate above
the spout of kettle to block the water vapour. Observe what you can see on the lower
surface of steel plate? Discuss in your class room

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Windy days

There is air everywhere
around us. Air is very
important to us. The moving
air is called as wind. The wind
is one of the major factor that
changes the weather. When
we see the environment around us, the branches and leaves
are moving, dust particles are flying, clothes in cloth line are
moving, etc. All these are seen due to the moving air. The air
sometimes blows gently and sometimes with a great speed.

The slow moving wind is called as breeze. Breeze makes a hot
and sunny weather pleasant. It also helps to dry our wet clothes.

The strong wind or fast moving wind is called as storm.
It is very strong and forceful. It may carry the rain also. It can
carry dust, papers, leaves, plastics, etc. at high speed over a
long distance. The strong storm is very destructive in nature.
It destroys various natural and man made structures like trees,
roofs of house, electric poles, etc. It may uproot the trees, break
the tree branches, remove the roofs of houses, destruct the
electric wires, etc. There are the chances of accidents to occur
in a stormy day. We feel difficulty to play, work, walk, etc. So,
it is better not to walk outside on the stormy days.

The movement of air on the earth is affected by heating
of the earth’s surface by the sun. When the earth’s surface is
heated, air nearer to it becomes hotter. Hot air is lighter than
the cold air and hence moves up. A gap is created on the earth’s
air surface when the warm air rises up. This gap is filled by
cool air coming from another place which produces a breeze.
In summer days, it becomes very hot and big gaps are formed
in short period of time leading to storms.

Blooming Science, Health and Physical Education Book 3 97

Activity: 2

Hold a ribbon and stand in any place outside your classroom. Observe the moving
ribbon and its direction. Find out the reason of movement of the ribbon and discuss
with your friends and teacher.

Cold days

We feel very difficult to
do our work in the winter
season. This is because in
winter season, the days are
very cold. During winter
season, the days are shorter
than the night. The sun lies far
from the earth and falls in a slanting way.
The animals remain inactive in winter season. The cold
blooded animals go for hibernation. The leaves of the trees fall
and looks dead. Human beings gather at a place and warm their
body by lighting a fire. The activities of human beings and other
animals can be seen when the sunlight warms the surroundings.
The himalayas and high hills are covered by snow. In other regions
also, the surface is found covered with fog, mist and frost.

In winter season, due to extreme cold, water turns into ice.
It is found on the surface of earth in the form of snow, mist, fog
and frost.

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Snowfall occurs in himalayas mainly in winter season.
Snow is the frozen rain. When cloud reaches a very high
altitude, due to extreme cold, rain drops freeze and changes
into solid form. This falls in the form of snow. In some areas,
frost can also be seen. When water vapour present in air is
extremely cooled, then it turns into solid and deposited over
the grasses and tree leaves in the form of frost.
Somtimes in winter, the places are not seen because they
are covered with fog and mist. Fog is a thick cloud which is
close to the ground. If this cloud is little thin, it is called as mist.
We feel cold when there is fog or mist. We can feel the water
drops on walking in fog or mist.

When the sun is blocked by the clouds or mist or fog we
feel cold. We also feel cold when there is snowfall and frost. It
is difficult to live in a very cold climate. We may suffer from
common cold and pneumonia. Road accidents also may occur
due to poor visibility in a foggy day. It may be slippery due to
the frost as well. We should wear warm clothes, eat hot foods
and liquids. We should be safe while driving in such conditions.
We should stay inside our house when there is a snowfall.

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Key words

slanting – sloping position / to slope

Evaporation – the process of changing water into water vapour.

Spout – a pipe or tube through which a liquid is poured.

Destructive – causing much damage.

Extreme – utmost, at very high degree

Freeze – change from liquid to solid state

Visibility – the state or fact of being visible.

Main Points to Remember

 Weather is the condition of a day. It is affected by the clouds, sunshine, rain and wind.

 There are different types of weather like sunny, cloudy, rainy and cold.

 Water vapour at cold place forms cloud and cloud carries the rain.

 The slow moving wind is a breeze and fast moving wind is a storm.

 The moving wind is destructive which may destruct the natural and manmade
things.

 Winter days are colder. In winters days we feel cold due to snow fall, fog, mist
and frost.

 The extreme cold is difficult to survive. We must be protective in cold winter season.

Project Work

Observe your environment for 3 days. Make a table as
given in your exercise copy and record the weather of different
time. Show it to your teacher and discuss it.

Days At 7:00 am At 1:00 pm At 5:0 pm
Day 1

Day 2

Day 3

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