Modern Concept Science 3

Fig: 5.10 Some desert plants

Aquatic plants (Hydrophytes)
Plants like lotus, water lily, water hyacinth, hydrilla, pistia, etc. grow in
water. They are called aquatic plants or hydrophytes. They have weak
stems and poorly developed roots. Some aquatic plants have large and
flat leaves. With the help of these leaves, they can float freely on water.

Memory Tips

Plants that grow in water are called aquatic plants or hydrophytes. Examples:
lotus, water lily, water hyacinth, hydrilla, pistia, etc.

Fig: 5.11 Some aquatic plants

E. Plants growing in summer and winter season

We cannot see all the plants throughout the year. Some plants grow in
summer season while others grow in winter. However, there are few
plants that grow in both the seasons.
Summer plants
Different kinds of plants like pumpkin, lady’s finger, cucumber, rice,
maize, soyabean, water melon, etc. grow in summer season. So, they are
called summer plants. Summer plants can adapt to hot climatic condition.

Memory Tips

Those plants which grow in summer season are called summer plants.
Examples: pumpkin, cucumber, rice, maize, soyabean, water melon, etc.

DIFFERENT TYPES OF PLANTS 43

Fig: 5.12 Some summer plants

Winter plants

Plants like spinach, cabbage, cauliflower, wheat, lentils, etc. grow in
winter season. So, they are called winter plants. These plants can adapt
themselves to cold climatic conditions.

Memory Tips

Those plants which grow in winter season are called winter plants. Examples:
spinach, cabbage, cauliflower, wheat, lentils, etc.

Fig: 5.13 Some winter plants

EXERCISE

1. Fill in the blanks using suitable words.
cactus flowers water winter mushroom herbs annual
a) Flowering plants bear ............................ .
b) ............................. does not bear flower.
c) Wheat, maize and pea are ............................ .
d) ............................. plants can live for one year.
e) ............................. is a desert plant.

44 Modern Concept Science, Health and Physical Education - 3

f) Water lily grows in ............................. .
g) Cauliflower grows in ............................. season.

2. Write ‘T’ for True and ‘F’ for Fasle statements.

a) Rose is a flowering plant.

b) Mushrooms do not bear flower.

c) Trees can live for many years.

d) Herbs have hard and woody stem.

e) Tomato is a tree.

f) Grass is a herb.

g) A rice plant can live for many years.

h) Lotus is an aquatic plant.

i) Plants growing in desert are called aquatic plants.

j) Watermelon grows in winter season.

3. Match the following:

Lotus desert plant
tree
Cactus aquatic plant
has no flowers
Grass herb

Mango

Mushroom

4. Identify trees, shrubs and herbs from the following figures.

DIFFERENT TYPES OF PLANTS 45

5. Identify terrestrial and aquatic plants from the following figures.

6. Answer the following questions.
a) What are trees? Give any four examples.
b) Define shrubs and give any four examples.
c) Why are shrubs called bushy plants?
d) Define herbs and give any four examples.
e) Define flowering and non-flowering plants with any two
examples of each.
f) What do you mean by annual plants? Give any four examples.
g) Define perennial plants with any three examples.
h) What are terrestrial plants? Give any four examples.
i) Define xerophytes with any three examples.
j) What are aquatic plants? Give any four examples.
k) Name any three summer plants.
l) Name any four winter plants.
Activity

From your surroundings, list any four each of flowering, non-
flowering, aquatic and terrestrial plants.

Project Work
Draw the pictures of lotus, rose and cactus. Also, colour them and
write their habitats in your project work copy.

46 Modern Concept Science, Health and Physical Education - 3

IMPORTANCE OF PLANTS Unit
AND ANIMALS
6

Estimated teaching periods : 5

Objectives d

After completing the study of this unit, students will be able to:
 state the importance of plants and animals.
 identify the materials obtained from plants and animals.

Warm up activity

Look, identify and say.

a bc

e f gh

i jkl

Can you say?

ƒƒ Can you identify the above figures?
ƒƒ Which of the above plants are used in vegetables?
ƒƒ Which are fruits in the above figures?
ƒƒ Which of the above animals are kept at our homes?
ƒƒ Which of the above animals is used to carry load

IMPORTANCE OF PLANTS AND ANIMALS 47

Plants and animals are equally important to us. We need food to eat,
clothes to wear and home to take shelter. Do you know where our
food comes from? All the foods that we eat come from different types
of plants and animals. We get grains, vegetables, fruits, medicines, etc.
from plants. We get milk, meat, eggs, etc. from animals. Besides these,
we get other materials like wood, cotton, leather, wool, fibre, etc. from
plants and animals.

Memory Tips

We get grains, vegetables, fruits, medicines, etc. from plants. Similarly, we
get milk, meat, eggs, etc. from animals. So, plants and animals are equally
important to us.

Fig: 6.1

Plants as food

We need food to live. Most of our food comes from plants. Plants produce
food by using carbon dioxide and water in the presence of sunlight. This
process is known as photosynthesis. Photosynthesis takes place only in
green leaves. The food produced by green plants is not used completely
by them. Thus, they store this food in different body parts like roots,
stems, leaves, fruits, etc. We eat these parts as our food.

Memory Tips
We eat leaves, roots, stems, fruits and seeds of different plants as our food.

48 Modern Concept Science, Health and Physical Education - 3

A. Cereals
Wheat, rice, maize and barley are some examples of cereals. Most of
our food comes from the cereals. They are rich in carbohydrates and
provide us energy to do work.
Memory Tips

Cereals are called energy giving foods. Examples: wheat, rice, maize and barley.

Fig: 6.2

B. Pulses
We get pulses from peas, grams, lentils, beans and kidney beans.
They are rich in proteins and help in growth and development of
the body.
Memory Tips

Pulses are called body building foods. Examples: peas, grams, lentils, beans,
kidney beans, etc.

Fig: 6.3

C. Vegetables
We get vegetables from different parts of the plants. In vegetables,
we eat roots, stems, leaves and flowers of plants.
Memory Tips

Roots, stems, leaves and flowers of the plants are used in vegetables.

IMPORTANCE OF PLANTS AND ANIMALS 49

i. Roots

We eat roots of carrot, radish, beetroot and turnip. They are rich in
vitamins and minerals.

Fig: 6.4

ii. Leaves

We eat leaves of cabbage, spinach and lettuce. They are rich in
vitamins and minerals.

Fig: 6.5

iii. Flowers

We eat flowers of cauliflower and broccoli. They are mostly used as

vegetables. They provide us vitamins and minerals.

Fig: 6.6

50 Modern Concept Science, Health and Physical Education - 3

iv. Stems
We eat stems of potato, onion and ginger. They are mostly used
in our vegetables. They provide us carbohydrates, vitamins and
minerals.

Fig: 6.7

D. Fruits
We eat fruits of some plants. They taste delicious. They provide
us vitamins and minerals. Some of the fruits that we eat are given
below:

Fig: 6.8

Plants as medicines

Plants like tulsi, mint, aloe, peepal, neem, babari, harro, barro, amla,
panchaunle, sarpagandha, etc. are used as medicines. They are used to
cure a large number of diseases.

Memory Tips

Different plants like tulsi, mint, aloe, peepal, neem, babari, harro, barro,
amla, panchaunle, sarpagandha, etc. are used as medicines.

IMPORTANCE OF PLANTS AND ANIMALS 51

Fig: 6.9

Fibres from plants

Plants like cotton, jute, and coconut give us fibres. They are used to
make clothes, nets, ropes, carpets, sacks, doormats, etc.

Fig: 6.10

Importance of animals

We use different kinds of animals. They give us food, fibres and leather.
We get meat, milk and eggs from animals. We get milk from cows, goats
and buffaloes. We need milk to grow strong and healthy. Milk is used to
make things like butter, cheese, ghee, curd, sweet and ice-cream.

Memory Tips
We get meat, milk, eggs, fibres, etc. from animals. So, they are very
useful to us.

Fig: 6.11 Some milk products

52 Modern Concept Science, Health and Physical Education - 3

Similarly, we get fibres from animals like sheep, rabbit, silkworm, etc.
We get wool from sheep and rabbit. We get silk from silkworm.
We get eggs from birds like hens, ducks and geese. Eggs are rich in
proteins.

Memory Tips
Animals like sheep, rabbit, silkworm, etc. are used to get fibres.

Fig: 6.12 Eggs
We get flesh from goat, sheep, chicken, fish and turkey. It is rich in
protein. It helps in growth and development of the body.

Fig: 6.13 Meat
We get honey and wax from beehives. Honey is rich in proteins, vitamins,
minerals and other nutrients.

Memory Tips

Goat, sheep, chicken, fish, turkey, etc. are used to get meat. Similarly, honey
and wax is obtained from honeybees.

Fig: 6.14 Products of honeybees

IMPORTANCE OF PLANTS AND ANIMALS 53

Animals used in transportation

Animals like horse, donkey, oxen, mules, etc. are used to carry
goods. They carry loads on their back. Carts are also pulled by these
animals. Carts carry goods and people. These are important means of
transportation in rural areas. Some animals like oxen, buffaloes are used
in ploughing the field.

Memory Tips
Some animals like horse, donkey, oxen, mules, etc. are used in
transportation to carry goods.

Fig: 6.15 Animals are used in transportation and ploughing the field

Animals as pet

Animals like white mouse, cat, rabbit, dog, etc. are kept at our homes.
They are called pet animals. Pet animals give us company and security.
Rabbit and white mouse add beauty and value to the house. Cats and
dogs give company. Cats also kill rats. Dog protects our house from
unknown people. Do you have a pet animal at your home?

Memory Tips
Those animals which are kept at our home are called pet animals.
Examples: white mouse, cat, rabbit, dog, etc.

Fig: 6.16 Pet animals

54 Modern Concept Science, Health and Physical Education - 3

Other uses

Skin of some animals is used for various purposes. It is used to make
shoes, bags, belts, purses, jackets, etc. Do you wear leather shoes? They
are made of animal leather.

Memory Tips

Leather shoes, bags, belts, purses, jackets, etc. are made from the skin
of animals.

Fig: 6.17

EXERCISE

1. Fill in the blanks using the correct words.

food water carbon dioxide fibres people dog
a) All living beings need ....................... to live.
b) Plants produce food by using ....................... and .......................……

in the presence of sunlight.
c) Plant ....................... are used to make clothes.
d) Carts carry goods and .......................
e) A ....................... protects our house from unknown people.

2. Write ‘T’ for True and ‘F’ for Fasle statements.

a) Roots of carrot are used in our food.

b) We get food from leaves of soyabean.

c) We get oil from the roots of mustard plant.

d) Tulsi plant is used as a medicine.

e) Roots of spinach are used as vegetable.

f) We make carpets from the fibres of jute plants.

g) Chickens are used to carry loads.

h) Cat is a pet animal.

i) Goats give us meat.

IMPORTANCE OF PLANTS AND ANIMALS 55

3. Choose the best answer from the given alternatives.

a) Wheat, rice and maize are ....................

i. pulses ii. cereals iii. vegetables

b) We eat .................... of potato and ginger.

i. leaf ii. root iii. stem

c) We get eggs from ....................

i. cow ii. goat iii.hen

d) .................... carries loads.

i. cow ii. dog iii. donkey

e) We get .................... from chicken and fish.

i. milk ii. meat iii. leather

f) .................... is a medicinal plant.

i. tulsi ii. tomato iii. cauliflower

g) .................... of animals is used to make shoes.

i. wool ii. leather iii. bones

4. Identify the following and state their uses.

5. Identify the following animals and state what we get from each of them.

6. Match the following:

Beehive pet animal
Sheep eggs
Lettuce honey
Hen wool
Cat transportation
Horse vegetable

56 Modern Concept Science, Health and Physical Education - 3

7. Answer the following questions.
a) Name any three things that we get from plants.
b) What is photosynthesis? In which part of the plant does it take
place?
c) Give any three examples of cereals.
d) Name any three plants from which we get pulses.
e) Name any three plants whose leaves are eaten as vegetables.
f) Give any three examples of medicinal plants.
g) Name any three things that we get from animals.
h) Name any three animals which carry our loads.
i) What are pet animals? Give any two examples.
j) Name any two animals whose leather is used for making shoes.

Activity

Observe various plants and animals in your locality and complete the
given table.

Plants Parts of plant Animals Uses
used as food
1. Cabbage Leaf 1. Goat ......................
2. .................. ...................... 2. .................. ......................
3. .................. ...................... 3. .................. ......................
4. ................... ...................... 4. ................... ......................
5. ................. ...................... 5. .................

Project Work

Paste the pictures of any five animals in your project work copy and
write their uses below the pictures.

IMPORTANCE OF PLANTS AND ANIMALS 57

Uni t

7 OUR ENVIRONMENT

Estimated teaching periods : 7

Objectives

After completing the study of this unit, students will be able to:
 state the importance of clean environment.
 explain various kinds of pollutions.
 state the ways to reduce pollution.

Warm up activity

Look, identify and say.
a

b

Can you say?

ƒƒ What kinds of environments are given in the above figures?
ƒƒ Which of the above environment do you like and why?
ƒƒ Which of the above environment you do not like and why?
ƒƒ Can we make our environment clean, how?
ƒƒ What can you do to make your home and school clean?

58 Modern Concept Science, Health and Physical Education - 3

Clean Environment

The place where we live in is

called environment. It includes

everything that surrounds us.

Soil, water, forest, rocks, animals,

plants, air, etc. are the parts of

environment. A clean and healthy

environment is very essential for

healthy life. We must keep our

environment clean and healthy

so that we can live in a healthy

manner. Fig: 7.1 Clean environment

Memory Tips

Our environment remains clean if the parts of environment like water, air,
soil, animals, plants, etc. are clean and healthy.

Dirty Environment

Nowadays, human beings have developed various technologies for
their use. Overuse of these technologies is creating problems in our
environment. We use vehicles to travel from one place to another. But,
the use of vehicles is causing problems in air making it unsuitable to
breathe. Similarly, we use plastic bags to carry different goods from one
place to another. They do not decay and cause soil pollution. In this way
our environment becomes dirty.

Memory Tips

Different kids of bad activities of human beings are very much responsible
for the degradation of the environment.

Fig: 7.2

OUR ENVIRONMENT 59

Dirty environment is the home for various kinds of insects and germs.
For example, if we throw the wastes here and there, insects like flies
and mosquitoes get a good environment to reproduce. As a result,
the number of insects and flies grows rapidly. Insects and flies transmit
various diseases to the human beings. So, it is our duty to manage the
kitchen wastes at our home properly and keep our environment clean.

Memory Tips

Dirty environment is responsible for causing various diseases in human
beings and other animals.

Fig: 7.3
Different kinds of wastes that are produced from our home, school,
offices, industries, etc. are divided into two types. They are:

i. Degradable wastes
ii. Non-degradable wastes
i. Degradable wastes
Degradable wastes include the wastes that are produced from using
plant and animal products. These wastes are mainly produced
in our kitchen. Besides kitchen, animal excreta, dead and fallen
parts of the plants are also included in this category. Degradable
wastes can be decomposed easily by the microorganisms present
in the environment. So, they do not pose a long-term threat to the
environment. Besides, human beings can also get benefit from the
degradable wastes. The degradable wastes can be converted into
compost manure that can be used in our agricultural farm or garden
to increase the fertility of soil.

60 Modern Concept Science, Health and Physical Education - 3

Memory Tips

Those wastes which can be decomposed easily by the microorganisms are
called degradable wastes. For examples, kitchen wastes, animal excreta,
dead bodies of animals and plants, etc.

Fig: 7.4

ii. Non-degradable wastes

Non-degradable wastes include plastic, metals, glass bottle, etc.
They do not degrade in the environment and remain in the same
form for a long time. That is why they degrade the quality of the
environment causing air, water and land pollution. Nowadays ,
the use of chemical fertilizers is also affecting the quality of soil.
Thus, we must try to limit the use of non-degradable things to the
minimum.

Memory Tips

Those wastes that cannot be decomposed easily by the microorganisms are
called non-degradable wastes. For examples, plastics, metal pieces, glass
pieces, etc.

Fig: 7.5

OUR ENVIRONMENT 61

Environmental pollution

Environment is the home for all living organisms. Healthy environment
is essential for healthy life. However, due to several human activities,
environment is losing its natural quality. Environmental pollution is
divided into three major types. They are:
i. Water pollution ii. Air pollution iii. Land pollution

Memory Tips

Different types of human activities such as open defecation, throwing wastes
in water bodies, deforestation, etc. are responsible for losing the natural
quality of the environment.

i. Water pollution
After air, water is one of the most essential components for the survival
of living beings. However, dirty water causes adverse impact on the
health of human beings and other animals. The sewage produced
from the human settlement and industries is the main cause of water
pollution. Polluted water affects both plants and animals.

Fig: 7.6
The consumption of polluted water can cause various diseases like
dysentry, cholera, diarrhoea, typhoid, jaundice, etc. So, we should not
drink polluted water. Besides causing diseases, polluted water can
create overall environmental problems. Thus, we should not throw
wastes near the sources of water and sewage should not be mixed in
water directly.

Memory Tips

The degradation in the quality of water due to mixing of various waste
materials is called water pollution.

62 Modern Concept Science, Health and Physical Education - 3

ii. Air pollution

Both animals and plants need air for respiration. Any kind of harmful
substance in the air can affect the health of organisms. Nowadays, air
is losing its quality due to the presence of excessive smoke and dust.
It is called air pollution. Overuse of vehicles, industries, factories, etc.
produces harmful smoke causing air pollution.

Fig: 7.7
Air pollution directly affects our respiratory system causing diseases
like asthma, bronchitis, conjunctivitis, etc. Thus, we must try to keep
our air clean and healthy. For this purpose, the use of private vehicles
should be minimized, industries should be located away from the human
settlements and people should be made aware about air pollution.

Memory Tips

The degradation in the quality of air due to mixing of various waste materials
is called air pollution.

iii. Land pollution

Land is the natural resource where we live, grow crops, build houses
and perform all other activities. The various human activities lose the
quality of land. It is called land pollution. It affects all the animals
and plants. The haphazardly thrown wastes and overuse of chemical
fertilizers are the main factors for land pollution.

Fig: 7.8

OUR ENVIRONMENT 63

Land pollution affects the fertility of the soil and reduces the production
of crops. As a result, we face the shortage of food. Thus, we must not
throw the wastes haphazardly and the use of chemical fertilizers should
be minimized.

Memory Tips

The degradation in the quality of land due to mixing of various waste
materials is called land pollution.

Methods of keeping the environment clean
1. We must try to manage the kitchen and garden wastes ourselves.
2. Degradable wastes should be converted into compost manure.
3. Non-degradable wastes should be reused or recycled.
4. We should defecate and urinate only in the toilet.
5. Trees should be planted to reduce the presence of harmful gases

in the air.
6. Drainage should be managed properly.
7. Domestic animals should not be taken to bathe in the sources of

water.
8. We should bathe and wash clothes away from the sources of

water.
Memory Tips
We can keep environment clean by using the environmental components
properly. To keep environment clean, we should manage degradable and
non-degradable wastes properly, we should stop open defecation, etc.

EXERCISE

1. Fill in the blanks using suitable words.

air clean environment pollutants healthy compost

a) .................... is the place where we live in.
b) Things that cause environmental pollution are called ....................

64 Modern Concept Science, Health and Physical Education - 3

c) A ................ and ............... environment is essential for healthy life.
d) Asthma is caused due to .................... pollution.
e) Degradable waste should be converted into .................... manure.

2. Write ‘T’ for True and ‘F’ for Fasle statements.

a) Environment should be kept dirty.

b) We should manage the kitchen waste properly.

c) Degradation in the quality of the environment is called pollution.

d) Air pollution mainly affects our digestive system.

e) Land pollution reduces the fertility of soil.

3. Choose the best answer from the given alternatives.

a) Clean environment is essential for ......................... .

i. prosperous life ii. healthy life iii. unhealthy life

b) Water pollution affects ......................... .

i. aquatic animals ii. human beings iii. all the organisms

c) Air pollution causes ......................... .

i. asthma ii. diarrhoea iii. jaundice

d) Land pollution reduces the ......................... of soil.

i. fertility ii. colour iii. property

e) We should use ......................... to defecate and urinate.

i. open place ii. riverside iii. toilet

4. Answer the following questions.
a) What do you mean by environment?
b) What type of environment is necessary for a healthy life?
c) What are degradable and non-degradable wastes?
d) What do you mean by pollution?
e) Define pollutants.
f) What are the effects of water pollution?

OUR ENVIRONMENT 65

g) What should we do to prevent water pollution?
h) What are the effects of air pollution?
i) State the methods of reducing air pollution.
j) Write down the causes of water and air pollution.
k) What are the causes of land pollution?
l) State the effects of land pollution.
m) How can we keep the land free from pollution?
5. Observe the following figures and compare them.

Activity
Ask your parents about the management of the wastes produced from
your home. Then, prepare a short report and present it in the class.

Project Work
Visit the sources of water around your school with your science
teacher. Take a photograph and paste it in your project work copy
and write a few lines about the status of water in that source.

66 Modern Concept Science, Health and Physical Education - 3

DIFFERENT TYPES Unit
OF MATTER
8

Estimated teaching periods : 3

Objectives d

After completing the study of this unit, students will be able to:
 identify the floating and sinking objects.
 state the differences between soluble and insoluble matter.
 differentiate between transparent and opaque objects.

Warm up activity

Look, identify and say.

a bc

e fg h

i jk

Can you say?

ƒƒ Which of the above examples are solid?
ƒƒ Can you identify liquids in the above figures?
ƒƒ Which of the above are gases?
ƒƒ In between sugar and soil, which is soluble in water?
ƒƒ Can you name other examples of solid, liquid and gas?

DIFFERENT TYPES OF MATTER 67

We can see many things around us. Most of these things present in our
surroundings are impure. Impure substances are also called mixtures,
because they are formed by mixing two or more substances. For
example, river water contains different types of minerals, salts, mud,
sand, etc. All the substances present in our surroundings occupy space
and have certain weight. These substances are called matter. Air, water,
soil, stone, vegetables, food, medicine, etc. are some examples of matter.

Memory Tips

Anything that occupies space and has mass is called matter. For examples,
Air, water, soil, stone, vegetables, food, medicine, etc.

Fig. 8.1 Things around us

States of matter

There are three states of matter. They are solid, liquid and gas.
Solid
Solids are mostly hard substances. They have definite shape and volume.
For example, pen, pencil, ball, table, brick, stone, etc.

Memory Tips

Those substances which have definite shape and volume are called solids.
Examples: pen, pencil, book, ball, table, brick, stone, ice, etc.

68 Modern Concept Science, Health and Physical Education - 3

Fig: 8.2 Some solid matter

Liquid

Liquids do not have any shape. They take the shape of the vessel in which
they are kept. However, they have definite volume. Liquids always flow
from higher level to the lower level. Oil, water, milk, kerosene, juice, etc.
are some examples of liquid.

Memory Tips

Those substances which have definite volume but no definite shape are
called liquids. Examples: oil, water, milk, petrol, kerosene, juice, etc.

Fig: 8.3 Some liquid matter

Gas
Gas does not have a fixed shape and volume. It takes the shape of the
vessel or container in which it is kept. For example, hydrogen, oxygen,
nitrogen, helium, water vapour, etc. Air is a mixture of gases. We cannot
see it but can feel it by our skin.

Memory Tips

Those substances that neither have fixed shape nor fixed volume are called
gases. Examples: hydrogen, oxygen, nitrogen, helium, water vapour, etc.

DIFFERENT TYPES OF MATTER 69

Fig: 8.4 Gaseous matter

Types of matter

We have different types of matter around us. Some matter are heavier
while others are lighter. Some dissolve in water while some don’t. Some
allow the light to pass through them while some don’t. Some float in
water while some sink.

Memory Tips

There are different types of matter in our surrounding. Among them, some
are lighter while some are heavier. Some are soluble while some are insoluble.
Some are transparent while some are opaque.

Floating and sinking matter

A piece of wood floats in water. This is because wood is lighter than
water. Things like plastic, wood, paper, leaves, etc. are lighter than
water. Therefore, they float in water. When you put a stone in water, it
sinks. This is because it is heavier than water. Other things like iron nail,
rock, marble, brick, etc. also sink in water.

Memory Tips

The things which are lighter than water float in it. Examples: plastic, wood,
paper, leaves, etc. Similarly, the things that are heavier than water sink in it.
Examples: rock, marble, brick, etc.

70 Modern Concept Science, Health and Physical Education - 3

Fig. 8.5 Things floating in water

Soluble and insoluble matter

Add little of salt in a glass of water. Stir the water by spoon. Does the salt
dissolve? Yes, salt dissolves in water. The things like sugar, salt, alum,
lemon juice, etc. dissolve in water. So, they are called soluble things.
Take a glass of water. Add little sand to it. Stir the water by spoon. Does
the sand dissolve? No, sand does not dissolve in water. The things like
stones, sand, soil, mud, flour, etc. do not dissolve in water. So, they are
called insoluble matter.

Memory Tips

Those things that dissolve in water are called soluble matter. Examples:
sugar, salt, alum, lemon juice, etc. Similarly, those things that do not dissolve
in water are called insoluble matter. Examples: stones, sand, soil, mud, flour,
etc.

Fig: 8.6

Transparent and Opaque Objects

Light can pass through the transparent objects. For example, glass, thin
plastic, clear water, etc. Similarly, light cannot pass through the opaque
objects. For examples: brick, stone, wood, thick paper, etc.

DIFFERENT TYPES OF MATTER 71

Memory Tips

The things through which light can pass are called transparent objects.
Examples: glass, thin plastic, clear water, etc. Similarly, the things through
which light cannot pass are called opaque objects. Examples: wood, thick
paper, thick plastic, metal plate, brick, etc.

Fig: 8.7 Transparent object Fig: 8.8 Opaque objects

Conductors and Non-conductors

We boil water in a kettle and cook rice in a pressure cooker. Why do we
use those utensils? We use those utensils because they get heated easily.
It means that they carry heat with them. These things are made of metal.
Metals become hot when we supply heat to them. Similarly, metal wires
pass electricity through them and are used to conduct electricity. Thus,
the substances that allow heat and electricity to pass through them are
called conductors. Copper, silver, gold, iron, zinc, aluminium, etc. are
some examples of conductors.

Memory Tips

Those substances that allow heat and electricity to pass through them are
called conductors. Examples: copper, silver, gold, iron, zinc, aluminium, etc.

Fig. 8.9 Conductors of heat and electricity

72 Modern Concept Science, Health and Physical Education - 3

Some substances like wood, plastic, rubber, etc. do not allow heat and
electricity to pass though them. They are called insulators or non-
conductors. Non-conductors like plastic, wood, paper, etc. are used in
making handles of cooking utensils and covering electric w ires.

Memory Tips

Those substances that do not allow heat and electricity to pass through them
are called insulators or non-conductors. Examples: wood, plastic, rubber, etc.

Fig. 8.10 Non-conductors of heat and electricity

EXERCISE

1. Fill in the blanks with suitable words.
sand opaque matter solids transparent soluble floats sinks insoluble

a) Anything that occupies space and has mass is called .................. .
b) .................. have definite shape and volume.
c) Stone .................. in water.
d) Plastic .................. in water.
e) Sugar is .................. in water.
f) .................. is insoluble in water.
g) Wood is an .................. object.
h) Chalk dust is .................. in water.
i) Glass is a .................. object.

DIFFERENT TYPES OF MATTER 73

2. Write ‘T’ for True and ‘F’ for Fasle statements.

a) There are three states of matter.

b) Salt is soluble in water.

c) Chalk dust is soluble in water.

d) Plastic is heavier than water.

e) Wood is lighter than water.

f) Stone sinks in water.

g) Light passes through wood.

3. Match the following:

Glass opaque object
floating object
Brick insoluble in water
soluble in water
Salt sinking object
transparent object
Sand

Wood

Nail

4. Choose the best answer from the given alternatives.

a) Liquids have definite ...................... .

i. shape ii. volume iii. both

b) Oxygen and nitrogen are ...................... .

i. solids ii. liquids iii. gases

c) Things that are heavier than water ...................... in it.

i. mix ii. float iii. sink

d) Things through which light cannot pass are called ............. objects.

i. transparent ii. opaque iii. shadow

e) Plastic is a ...................... of heat and electricity.

i. non-conductor ii. semi-conductor iii. conductor

74 Modern Concept Science, Health and Physical Education - 3

5. Identify the following objects and write whether they are
conductors or insulators.

6. Answer the following questions.
a) What is matter? Give any three examples.
b) What are three states of matter?
c) What are solids? Give any three examples.
d) Define liquids with any three examples.
e) What are gases? Give any two examples.
f) Define soluble and insoluble matter with any two examples of
each.
g) Define transparent and opaque objects with any two examples
of each.
h) What are conductors and insulators? Give any two examples.
Activity

1. Take six glasses and fill them with water. Add some salt, sand,
sugar, chalk powder and ink separately. Which substances dissolve
in water and which do not? List them in different groups.

2. Make a list of four soluble substances and five insoluble ones that
are found at your home.

3. Observe the following figures and write short note on them.

DIFFERENT TYPES OF MATTER 75

Project Work

Take thin plastic, glass, wooden board, metal plate, muddy water and
clean water. Place them on the ground and check whether sunlight
passes through them or not. Fill your findings as shown in the table.

Matter Results
1. Thin plastic Transparent

2. ..................................... ....................................

3. ..................................... .....................................

4. ..................................... .....................................

5. ..................................... .....................................

6. ..................................... .....................................

7. ..................................... .....................................

76 Modern Concept Science, Health and Physical Education - 3

IMPORTANCE OF Unit
AIR AND WATER
9

Estimated teaching periods : 2

Objectives

After completing the study of this unit, students will be able to:
 explain the importance of air and water.
 name various sources of water.
 explain the effects of wind and storm.

Warm up activity

Look, identify and say. b c
a

d ef

g hi

Can you say?

ƒƒ Can you identify the above figures and activities?
ƒƒ Which of the above activities are importance of air and water?
ƒƒ Which of the above activities are not possible in absence of water?
ƒƒ Can you say some more importance of air?
ƒƒ What would happen if there no air and water?

IMPORTANCE OF AIR AND WATER 77

A. Air

There is air everywhere in our surroundings. We cannot see air but we
can feel it. Air occupies space and also has weight. Air is the gaseous
state of matter. Air contains many gases like oxygen, nitrogen, carbon
dioxide, water vapour, etc. Not only gases, air also contains small dust
particles. We need air for breathing. If we do not breathe just for a few
minutes, we will die. Do you know which gas we breathe in?

Memory Tips

Air is a mixture of different gases like oxygen, nitrogen, carbon dioxide,
water vapour, etc. Air occupies space and also has weight.

Fig: 9.1
The earth is surrounded by a mixture of different types of gases. This
mixture of different types of gases is called atmosphere. As we go up
in the high mountains, the amount of air decreases. This makes the
atmosphere thinner. Thus, mountain trekkers feel difficulties while
trekking.
In high mountains, there is less amount of oxygen. It is not sufficient
for the mountaineers to breathe. So they carry oxygen cylinder on their
back.

Memory Tips

The earth is surrounded by a mixture of different types of gases called
atmosphere. As we go up in the high mountains, the thickness of atmosphere
decreases

78 Modern Concept Science, Health and Physical Education - 3

Fig: 9.2
On the earth, air moves from one place to another. Sometimes it moves
gently but sometimes it moves with a great speed. The air moving slowly
and gently is called breeze. Breeze makes us cool and fresh. Wind is an
example of slow moving air. Strong wind is called storm. It may be
dangerous. Soil, dust, small pieces of woods, papers, clothes, roots of
plants, roofs of houses, electric poles and even men can be blown away
by storms. We must be careful during storms; the best thing is to stay
indoors.

Memory Tips
The air moving slowly and gently is called breeze. Breeze makes us cool and
fresh. Similarly, Strong wind is called storm. It may be dangerous.

Fig: 9.3

Importance of air

Air is one of the most important things for living beings. Without air,
no living thing can survive. Some common uses of air are given below.
i. Air is necessary for living beings to breathe.
ii. Plants need air to prepare their food.

IMPORTANCE OF AIR AND WATER 79

iii. Air is essential to burn substances.
iv. Air runs wind mills.
v. Balls, balloons and tyres need air to inflate them.
vi. Air also helps to dry our clothes.
viii. We need air to fly kites.

Memory Tips

Air is important for breathing, photosynthesis, burning fire, running wind
mills, to fill in the balloons and tubes, to dry clothes, to fly kites, etc.

Fig: 9.4 Uses of air

B. Water

After air, water is another very important thing for us. Water is present
in the body of all living beings. Our body also contains more than 70%
of water.

Memory Tips

After air, water is very important thing for all living things. It is a liquid
matter but it also occurs in solid (ice) and gas (vapour).

Sources of water
About three-fourths of the earth’s surface is covered with water. Only
about 29% of the earth’s surface is land. Rain, rivers, ponds, wells and
mountain snow are some sources of water. Large amount of water is
present in the seas and oceans. The water of seas and oceans is salty. So,
this water is not fit for drinking. We can drink the water of the rivers,
ponds, wells, and collected rainwater. But the water we drink must be
clean and pure. Rainwater is considered to be the purest form of water.

80 Modern Concept Science, Health and Physical Education - 3

Memory Tips

Rain, rivers, ponds, wells, mountain snow, seas, oceans, etc. are some sources
of water. Rainwater is considered to be the purest form of water but sea and
ocean water is not fit for drinking.

Fig. 9.5 Different sources of water

Importance of water
i. We use water for drinking purpose.
ii. We need water for cooking food.
iii. We need water for bathing and washing clothes.
iv. Water is necessary for fishing.
v. Water is used for boating.
vi. Plants need water to prepare their food.
vii. Water is used to generate electricity.
viii. We use water to douse fire.
ix. We use water for irrigation.

Memory Tips

Water is used for drinking, cooking, bathing, washing, fishing, boating,
generating electricity, dousing fire, irrigation, etc.

Fig. 9.6 Different uses of water

IMPORTANCE OF AIR AND WATER 81

EXERCISE

1. Fill in the blanks with appropriate words.
breeze inflate gases storm salty drinking

a) The mixture of various ..................... is called atmosphere.
b) ..................... makes us cool and fresh.
c) Strong wind is called .....................
d) Air is used to ..................... balloons.
e) Sea water is ..................... So it is unfit for ..................... .
2. Write ‘T’ for True and ‘F’ for False statements.

a) We need air to breathe.

b) In mountains there is more air.

c) Breeze is a fast moving air.

d) Plants also need air to breathe.

e) Storm can destroy electric poles and roofs of houses.

f) Rainwater is one of the purest forms of water.

g) We can drink sea water.

h) Water is used to generate electricity.

3. Answer the following questions.
a) Define atmosphere.
b) What do you mean by breeze?
c) Write any four uses of air.
d) How is breeze different from storm?
e) What are different sources of water? Name any four of them.
f) Write any four uses of water.
g) Why is ocean water unfit for drinking?

82 Modern Concept Science, Health and Physical Education - 3

4. Use the given clues to supply answers to the following:
a) I am a solid form of water.
b) Ha...Ha....Ha.... I am very pure form of water.
c) I come out from the water when they heat me. Who am I?
d) No one can catch me. You can only breathe me. I exist all over
the earth.
e) No one can drink me. I have too much salt with me.
f) You like me in summer season. I blow softly and gently.
g) I am very strong. I can also blow you away if you come outfrom
your house when I am active.
h) I generate electricity. You use electricity given by me. Say whoI
am and use me properly.
i) Three-fourths of my surface is covered by water. Can you guess
who I am?

5. Observe the following figures and write the conditions required
for them.

Activity
Which water do you drink, boiled water/filtered water/tap water? Ask
your parents how we can purify water for drinking. List the methods.

Project Work
Draw pictures of any two sources of water in your project work copy
and colour them.

IMPORTANCE OF AIR AND WATER 83

Uni t

10 WINDY DAY

Estimated teaching periods : 2

Objectives

After completing the study of this unit, students will be able to:
 distinguish between wind and storm.
 explain the effects of wind and storm.
 compare the positive and negative aspects of wind and storm.

Warm up activity

Look, identify and say.
a

b

Can you say?

ƒƒ Can you identify the effect of wind and storm in the above diagrams?
ƒƒ Have you seen the effect of storm?
ƒƒ What should we do when storm comes?
ƒƒ Can you say the importance of wind in our daily life?

84 Modern Concept Science, Health and Physical Education - 3

The earth is surrounded by the mixture of different gases called
atmosphere. In atmosphere, air does not remain at rest; it is in continuous
motion. Sometimes, it moves fast and sometimes slowly. The slow
moving air is called wind or breeze. In slow moving air, leaves of plants,
dust particles, papers, etc. move here and there in the sky. It is very
useful to us. It helps in drying clothes and grains. In slow moving air,
we feel easy to breathe. The breeze gives us a pleasant feeling in the
summer season.

Memory Tips

The slow moving air is called wind or breeze. In slow moving air, leaves of
plants, dust particles, papers, etc. move here and there in the sky.

Fig. 10.1 Effects of wind

Storm

The fast moving air is called storm. It can carry Effects of storm
dust, papers, leaves, plastics, etc. at a high speed Fig. 10.2
and over a long distance. The fast moving air is
very strong and forceful. So, it is very destructive
in nature.

Storm destroys various natural and manmade
structures like trees, roofs of houses, electric
poles, etc. During stormy days, it is difficult to
play, walk and work as the storm exerts great
force against our body.

Memory Tips

The fast moving air is called storm. It is very destructive. It can carry dust,
papers, leaves, plastics, etc. at a high speed and over a long distance.

WINDY DAY 85

Effects of storm
There is a greater chance of accidents on a stormy day. The force of
storm may blow away the tin roofs of houses. If such tin hits a person
walking on the road, he may die or get seriously injured. Similarly, the
broken branches of trees may cause road accidents. If the dust particles
carried by the wind enter in our eyes, we face eye problems. Thus, it is
better not to walk outside on stormy days.

Memory Tips

Storm is very destructive. It can carry dust, papers, leaves, plastics, etc. at
a high speed and over a long distance. It can uproot plants, blow roof of
houses, etc.

Fig: 10.3 Accidents due to storm
Storms generally occur during the warm summer days. The strong
heating of the earth’s surface due to intense sunlight causes the air to
rise up. A gap is created on the earth’s surface when the warm air rises
up. This gap is filled by cool air coming from another place. In this way,
storm takes place in the summer season. Thus, the strength of storm
depends upon the intensity of the sunlight and gaps in the atmosphere.

Fig: 10.4
The storm not only affects the man-made structures, but also the natural
things. Most of the plants have flowering period during the beginning
of summer season. Thus, the storm destroys the flowers of the plants.
Besides, storm also destroys the branches of the trees. In some cases, the
storm even uproots the trees.

86 Modern Concept Science, Health and Physical Education - 3

Memory Tips

Storm destroys the flowers of the plants. In deserts, storm carries a large
amount of sand from one place to another. As a result, sand dunes are formed.

Fig: 10.5 Effects of storm

Importance of wind

Wind not only has bad impacts on the environment, it also has some
good impacts. Wind carries pollens from one plant to another and
helps in pollination. The cold air flowing from the cold area makes
the surroundings cool and pleasing. It also decreases the temperature.
Thus, wind has both positive and negative impacts on the environment
and human beings.

Memory Tips

Wind helps in drying clothes and seeds, pollination in flowers, cooling the
surrounding, decreasing the temperature of the surrounding, etc.

Fig: 10.6 Positive aspects of wind

WINDY DAY 87

EXERCISE

1. Fill in the blanks using the correct words.
storm pollen grains summer stormy earth pollination

a) The .................... is surrounded by the atmosphere.
b) The fast moving air is called .................... .
c) There is greater chance of accidents on .................... days.
d) Storm generally occurs during warm .................... days.
e) Wind carries .................... and helps in .................... .

2. Write ‘T’ for True and ‘F’ for Fasle statements.

a) The mixture of different gases surrounding the earth is called
atmosphere.

b) The fast moving air is called wind.

c) Storm only affects man-made things.

d) Wind helps to disperse pollen grains.

e) Wind makes the surroundings cool.

3. Match the following:

Storm sand dunes
slow moving air
Desert

Pollination fast moving air

Atmosphere transfer of pollens

Breeze mixture of gases covering the earth

4. Choose the best answer from the given alternatives.

a) Fast moving air is called .........................

i. storm ii. wind iii. both

b) ......................... destroys natural and manmade structures.

i. breeze ii. wind iii. storm

88 Modern Concept Science, Health and Physical Education - 3

c) Wind makes the surroundings .........................

i. cool ii. warm iii. rainy

d) d. Warm air .........................

i. moves horizontally ii. rises up iii. stays as it is

e) e. Generally, storm is .........................…to us.

i. harmful ii. useful iii. useful and harmful

5. Answer the following questions.

a) What is atmosphere?

b) Define wind and storm.

c) How does storm develop?

d) Write any three adverse impacts of storm.

e) What are the positive effects of wind in the environment?
6. Observe the following figures and write short notes on them.

Activity

Have you observed the windy days? What kind of effects of wind
have you seen? Share in your class.

Project Work

Collect the pictures of windy day, stormy day, cold day, and hot day.
Write in your project work copy the differences you find among them.

WINDY DAY 89

Uni t

11 COLD DAY

Estimated teaching periods : 1

Objectives

After completing the study of this unit, students will be able to:
 state how the days become cold.
 name the types of clothes that should be used in cold days.

Winter is very cold. We feel difficulties to do any kinds of activities in the
winter days. Our body remains inactive due to the cold. During winter
season everything remains ugly. Most of the animals hide to protect
themselves from cold. The leaves of trees fall and look like dead. Human
beings gather at a place and warm their body in fire. The activities of
human beings and other animals can be seen when the sunlight makes
the surroundings warm.

Memory Tips

The days of the winter seasons are very cold. We cannot perform normal
activities in the cold days. Similarly, most animals hide to protect from cold.

Fig: 11.1 Fig: 11.2 Snowfall
Due to extreme cold, water turns into ice.
In winter season morning fog covers the
surroundings and makes everything invisible.
In some areas, frost can also be seen which
further makes the environment cold. In case of
Himalayas and polar regions, snow fall can be
observed during the winter.

90 Modern Concept Science, Health and Physical Education - 3

Snow is the frozen rain. The drops of rain when cooled, turn into snow
and fall on the earth’s surface as snow fall. Most of the people living in
the Himalayan region migrate to the hills during winter. That is why
they can escape themselves from the extreme cold. Though there are
least chances of communicable disease being spread in the cold days,
common cold is the most common disease seen in winter season.
The extreme condition of common cold may lead to fever and finally
pneumonia.

Memory Tips

It is very essential to put on warm clothes during winter to keep our body
safe from cold. The clothes that are used in winter include jacket, sweater,
woolen cap, woolen gloves, socks, trousers, etc.

Fig: 11.3 Some effects of cold
In winter season, there is greater chance of road accidents as fog covers
the surroundings and makes things invisible. Besides this, in some
countries, snowfall covers the roads blocking the transportation. If
vehicles move on such roads, they skid away and meet with accidents.
The extreme cold may result in frost bite. Frost bite mainly affects our
fingers and makes it unable to move them. In some extreme cold cases,
blood circulation totally stops and takes the life of the victim.

Memory Tips

In extreme cold, there may happens road accident, frost bite, common cold,
pneumonia, etc. It also may stop blood circulation.

COLD DAY 91

Fig: 11.4

EXERCISE

1. Fill in the blanks with suitable words.

Himalayan common cold death cold warm

a) The days of winter season are ...................... .
b) In winter, we should wear ...................... clothes.
c) In winter season, people mostly suffer from ...................... .
d) Extreme cold may cause ...................... .
e) Snowfall occurs in the ...................... region.

2. Write ‘T’ for True and ‘F’ for Fasle statements.

a) We feel cold during the winter season.

b) In winter season, water changes into ice.

c) In morning, fog makes everything visible.

d) Pneumonia is caused if we expose our body to cold.

e) Frost bite mainly affects our fingers.

3. Choose the best answer from the given alternatives.

a) Winter season is very ..................... .

i. hot ii. warm iii. cold

b) Fog covers the surroundings during the ..................... .

i. noon ii. morning iii. evening

92 Modern Concept Science, Health and Physical Education - 3