Science 7

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bigger since it is nearer from the earth. The moon completes its revolution
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The satellites which are made by human beings
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are computerized spacecrafts designed to revolve
around the earth in a particular orbit. There are
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i) For the communication of T.V., radio, telephone signals, etc.
ii) For forecasting weathers
iii) To study about the space and different parts of the earth.
iv) To make space station.

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Comets are those heavenly bodies which move around the sun in very large
elliptical path. Sometimes they come very close to the sun, sometimes very
far from the sun. When they come near the sun, tail is developed. When
they lie far away from the sun, the tail disappears. Due to the presence of
the tail, they are called tailed stars. But they are not the true stars.

Their body is composed of dust, gases, rocks, ice, etc. When they come near
the sun, the gases and the dust evaporate and tail is formed.

Halley’s comet, Enke, Shoemaker Levy, Temple Tutle, etc are some
important comets.

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Times' Crucial Science and Environment 247 Book 7

earth’s atmosphere during their fall to the earth. When they fall towards
the earth’s surface, they start burning due to friction with atmosphere.
Since they fall with streak of light, they are also called shooting stars.
If the mass of such objects is big and is not completely burnt in the
atmosphere, it can reach the earth surface. It is called meteorite. Such
meteorite can make craters on the earth surface.
It is said that meteors and meteorites are formed from the particles left off
by comets and pieces of collided asteroids.

Meteor

Meteorite

Differences between Meteor and Meteorite

Meteor Meteorite

ϭ͘ /ƚ ŝƐ Ă ƌŽĐŬLJ ƐƵďƐƚĂŶĐĞ ǁŚŝĐŚ ƉƌŽĚƵĐĞƐ ϭ͘ /ƚ ŝƐ Ă ďŝŐ ŵĞƚĞŽƌ ǁŚŝĐŚ ĚŽĞƐ ŶŽƚ

ůŝŐŚƚ ǁŚĞŶ ŝƚ ĞŶƚĞƌƐ ƚŚĞ ĞĂƌƚŚ͛Ɛ ĐŽŵƉůĞƚĞůLJ ďƵƌŶ ŽƵƚ ŝŶ ƚŚĞ ĞĂƌƚŚ͛Ɛ

ĂƚŵŽƐƉŚĞƌĞ ĚƵƌŝŶŐ ŝƚƐ ĨĂůů ƚŽǁĂƌĚƐ ƚŚĞ ĂƚŵŽƐƉŚĞƌĞ ĂŶĚ ĐĂŶ ƌĞĂĐŚ ƚŚĞ ĞĂƌƚŚ

ĞĂƌƚŚ͘ ƐƵƌĨĂĐĞ͘

Ϯ͘ /ƚ ŚĂƐ ƐŵĂůůĞƌ ŵĂƐƐ͘ Ϯ͘ /ƚ ŚĂƐ ďŝŐŐĞƌ ŵĂƐƐ͘

ϯ͘ /ƚ ĐĂŶ Žƌ ĐĂŶŶŽƚ ƌĞĂĐŚ ƚŚĞ ƐƵƌĨĂĐĞ ŽĨ ϯ͘ /ƚ ĐĂŶ ƌĞĂĐŚ ƚŚĞ ƐƵƌĨĂĐĞ ŽĨ ƚŚĞ ĞĂƌƚŚ͘
ƚŚĞ ĞĂƌƚŚ͘

Stars

You must have seen stars in the sky at clear night. They twinkle. They
have their own heat and light. They produce light due to nuclear reaction
taking place in them.

The heavenly bodies which have their
own heat and light produced due to
nuclear reaction are called stars.

There are billions of stars in the universe.
Our sun is also a star. It is a medium
sized star. There are many stars bigger
than the sun. They appear smaller
because they are very far from us.

The hottest stars are blue coloured.

Times' Crucial Science and Environment 248 Book 7

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minimum temperature are red in colour. They have the temperature
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Differences between planets and stars

Planets Stars

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ŵŽǀĞ ĂƌŽƵŶĚ ƚŚĞ ƐƵŶ͘ ŚĂǀĞ ƚŚĞŝƌ ŽǁŶ ůŝŐŚƚ ƉƌŽĚƵĐĞĚ ďLJ

ŶƵĐůĞĂƌ ƌĞĂĐƟŽŶ ƚĂŬŝŶŐ ƉůĂĐĞ ŝŶ ƚŚĞŵ͘

Ϯ͘ dŚĞLJ ĚŽ ŶŽƚ ŚĂǀĞ ƚŚĞŝƌ ŽǁŶ ůŝŐŚƚ͘ Ϯ͘ dŚĞLJ ŚĂǀĞ ƚŚĞŝƌ ŽǁŶ ůŝŐŚƚ͘

ϯ͘ ^ĂƚĞůůŝƚĞƐ ŵŽǀĞ ĂƌŽƵŶĚ ƚŚĞ ƉůĂŶĞƚƐ͘ ϯ͘ WůĂŶĞƚƐ ŵĂLJ ŵŽǀĞ ƌŽƵŶĚ ƚŚĞ ƐƚĂƌƐ͘

ϰ͘ dŚĞLJ ĂƌĞ ůĞƐƐ ŝŶ ŶƵŵďĞƌ͘ ϰ͘ dŚĞLJ ĂƌĞ ƵŶĐŽƵŶƚĂďůĞ ŝŶ ŶƵŵďĞƌ͘
ϱ͘ dŚĞLJ ĂƌĞ ŶŽƚ ŚŽƚ͘ ϱ͘ dŚĞLJ ĂƌĞ ĞdžƚƌĞŵĞůLJ ŚŽƚ͘

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When you observe the sky at clear night, you can see many stars. Some
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not change their shape although they change their positions. They are
constellations.
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change their shape even though they change their positions.
There are 88 constellations, out of which 12 constellations are used as
signs of zodiac. They are named after the names of gods, animals, heroes,
etc. Orion, Scorpio, Cassiopeia, Ursa major, etc are some important
constellations.

Ursa Major

It is common and easily noticeable in the
northern sky. It consists of 7 stars arranged
like the shape of a big question mark. It is
also called big dipper or great bear. In Hindu
mythology, it is called Saptarishi.
This constellation helps to identify the Polar
star.

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It is a ’W’ shaped constellation. It consists of
5 stars. The Ursa major and Cassiopeia are
at equal distance from the Polar star.

Times' Crucial Science and Environment 249 Book 7

Orion

It consists of the stars which are arranged
forming the shape of hunter. It consists
of three bright stars forming the belt of
hunter. There are some faint stars below the
belt forming the sword of the hunter. There
are two brightest stars in this constellation.
They are Betelgeuse (Punarvasu) on the
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left knee of the hunter.

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ŚƌŽŵŽƐƉŚĞƌĞ ͗ ƚŚĞ ŵŝĚĚůĞ ůĂLJĞƌ ŽĨ ƚŚĞ ƐƵŶ

ŽƌŽŶĂ ͗ ƚŚĞ ŽƵƚĞƌŵŽƐƚ ůĂLJĞƌ ŽĨ ƚŚĞ ƐƵŶ

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1. Solar system is a group of the sun, eight planets and their satellites,
comets, asteroids, etc which move around the sun.

2. Planets are the heavenly bodies which move around the sun.
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4. Venus is the hottest and brightest planet of the solar system.
5. Earth is the only living planet of solar system.
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8. Saturn is the second largest planet of the solar system.
9. Uranus is the second farthest planet from the sun.
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11.Satellite is a heavenly body which moves around the planet.
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13.Comets are those heavenly bodies which move around the sun in

very large elliptical paths.
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the earth’s atmosphere during their fall towards the earth.
15.If the mass of meteor is bigger, it does not burn completely and can

reach the surface of the earth. It is called meteorite.
16.Stars are heavenly bodies which have their own light and heat

produced due to nuclear reaction.

Times' Crucial Science and Environment 250 Book 7

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do not change their shape although they change their positions.

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1. Choose the best alternative in each case.
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i. Corona ii. Chromosphere

iii. Photosphere iv. Thermosphere

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L [ 7 NP LL [ 7 km
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d. Which planet of the solar system has the largest number of
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i. Due to enormous size of the sun
ii. To receive light from the sun
iii. Due to their nearness to the sun
iv. Due to the gravitational force of the sun

2. Fill in the blanks with appropriate words.

a. The sun is the ……….. star from the earth.

b. Planets move around the sun in ……………..

c. …………… is called morning and evening star.

d. ………………..is the largest planet.

e. …………….is the main satellite of Saturn.

f. …………….produce tails when they come near the sun.

3. Classify the following into constellation, satellite, planet and comets.

Triton, Titan, Scorpio, Shoemaker Levy, Orion, Cassiopeia, Temple
Tutle, Enke, Nereid, Uranus

4. Name the following planets:

Nearest planet, largest planet, brightest planet, farthest planet,
second largest planet, morning star, red planet

Times' Crucial Science and Environment 251 Book 7

5. Answer these questions in short.
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6. Differentiate between:

i. Planets and stars
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7. Draw a diagram of solar system and label all members.

8. Observe the following table and answer the questions:

Planet Disttahnecseufnrom Time of rotation reTviomluetoiof n

$ ð 7 km 243 days 225 days

B ð 7 km 24 days 365 days

C ð 7 km KRXUV 12 years

D ð 7 km KUV PLQ 29.5 years

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d. Name the natural satellite of planet B.

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Name any two of them.

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Times' Crucial Science and Environment 252 Book 7

Chapter

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ƐƟŵĂƚĞĚ ƉĞƌŝŽĚƐ͗ϭϯ

OBJECTIVES

At the end of the lesson, the students will be able to :
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 ĞdžƉůĂŝŶ ƚŚĞ ŶĞĞĚ ĂŶĚ ŝŵƉŽƌƚĂŶĐĞ ŽĨ ŶĂƚƵƌĂů ƌĞƐŽƵƌĐĞƐ ĂŶĚ ƐĂŶĐƚƵĂƌŝĞƐ͘
 ĚĞƐĐƌŝďĞ ǁĂƚĞƌ ƌĞƐŽƵƌĐĞ͕ ǁĞƚ ůĂŶĚƐ͕ ĂŶĚ ǁĂƚĞƌ ƐŚĞĚƐ ǁŝƚŚ ƚŚĞŝƌ

ŝŵƉŽƌƚĂŶĐĞ ĂŶĚ ĐŽŶƐĞƌǀĂƟŽŶ ŵĞĂƐƵƌĞƐ͘
 ĞdžƉůĂŝŶ ƚŚĞ ŝŶƚĞƌƌĞůĂƟŽŶƐŚŝƉ ĂŵŽŶŐ ƉƌŽĚƵĐĞƌƐ͕ ĐŽŶƐƵŵĞƌƐ ĂŶĚ

ĚĞĐŽŵƉŽƐĞƌƐ͘

MIND OPENERS
 tŚĂƚ ĚŽ LJŽƵ ŵĞĂŶ ďLJ ŶĂƚƵƌĂů ƌĞƐŽƵƌĐĞƐ ͍ tŚLJ ĂƌĞ ƚŚĞLJ ŝŵƉŽƌƚĂŶƚ͍
 ,Žǁ ĂƌĞ ŶĂƚƵƌĂů ƌĞƐŽƵƌĐĞƐ ƉƌŽƚĞĐƚĞĚ͍
 ĂŶ LJŽƵ ŶĂŵĞ ƐŽŵĞ ŶĂƟŽŶĂů ƉĂƌŬƐ ĂŶĚ ǁŝůĚůŝĨĞ ĐŽŶƐĞƌǀĂƟŽŶ ĂƌĞĂƐ͍

ŝƐĐƵƐƐ͘

Introduction

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consists of natural resources which are regarded as the main supporters of
life on the earth.

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The useful substances found naturally on the earth are known as natural
resources. $LU ZDWHU VRLO URFNV PLQHUDOV ZLOGOLIH IRUHVW HWF DUH WKH
natural resources.

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their natural availability. They are:

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2. Non- renewable natural resources

3. Perpetual natural resources

1. Renewable natural resources
The natural resources which cannot be produced again by natural cycles
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forest, etc.

Times' Crucial Science and Environment 253 Book 7

2. Non-renewable natural resources
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and cannot be produced again are called non-renewable natural resources.
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etc. are non-renewable natural resources.
3. Perpetual natural resources
The natural resources which neither increase nor decrease in spite of their
continuous use are called perpetual natural resources. )RU H[DPSOH DLU
wind energy, solar energy, etc.

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The life on the earth is possible due to the availability of natural resources
and other conditions. The importance of natural resources can be
summarized in the following points:

Drinking water Planting paddy ornGaomldent Gas

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It also contains CO2 which is used by plants to prepare food. The air

also helps to sail boats, run windmills, etc.

2. Water is used for drinking, cooking foods, washing clothes and utensils,
bathing, cleaning, etc. It is also used to produce hydroelectricity, in
irrigation, industrial purpose, etc.

3. Soil is used to grow crops, fruit plants and other plants. It is the home
of several living organisms.

4. We obtain minerals, metals and rocks from the earth. The minerals
such as quartz, talc, gypsum, diamond, graphite, ruby, garnet, calcite,
etc are used for different purposes. The metals, as studied earlier, are
very useful to us.

Three types of rocks- igneous, sedimentary and metamorphic rock,
are found on the earth. These rocks are widely used in construction
and in making several useful materials.

Times' Crucial Science and Environment 254 Book 7

5. Coal and petroleum found on the earth’s crust are the main source
of energy. Their use ranges from domestic purpose to the running of
vehicles, aircrafts and industries.

6. The plants are very useful natural resources. They provide food and
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rubber, paper, etc from plants.

7. The wild life are also useful. We get several things from them.

8. The sun is the main source of heat and light for the earth. It can be
used as a convenient alternative source of energy.

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The natural heritage includes the naturally occurring wealth of a country.
Forest, wildlife, watersheds, etc are the natural heritages. Nepal was very
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growth and migration of people from one area to another has resulted in
heavy depletion of forest and wild life. Thus, there is a need of conserving
nature and natural heritages. In order to protect the wildlife and other
natural resources, wildlife conservation areas and national parks have
been established at different parts of our country.

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A national park is a separate piece of land protected for the proper
management and conservation of wildlife together with their natural
environment. 7KH QDWLRQDO SDUNV KHOS WR FRQVHUYH WKH ÁRUD IDXQD DQG
natural scenery of a particular area. Since the national parks are rich in
natural beauty and resources, they attract tourists. The important national
parks of Nepal are given below:

S.N. EĂƟŽŶĂů WĂƌŬƐ >ŽĐĂƟŽŶ Area Year of Prominent animals
(sq. km) establishment

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WĂƌŬ DĂŬǁĂŶƉƵƌ ĂŶĚ ƌŚŝŶŽĐĞƌŽƐ͕ ĐƌŽĐŽĚŝůĞ͕ ĚĞĞƌ͕
WĂƌƐĂ ĚŝƐƚƌŝĐƚƐ ůĞŽƉĂƌĚ͕ ƐĞǀĞƌĂů ƐƉĞĐŝĞƐ ŽĨ

ďŝƌĚƐ ĂŶĚ ďƵƩĞƌŇŝĞƐ

Ϯ͘ ZĂƌĂ EĂƟŽŶĂů WĂƌŬ DƵŐƵ ĂŶĚ :ƵŵůĂ ϭϬϲ ϮϬϯϮ ͘^͘ DƵƐŬ ĚĞĞƌ͕ ,ŝŵĂůĂLJĂŶ
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ŝŶĐůƵĚĞƐ ZĂƌĂ >ĂŬĞ
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^ŶŽǁ ůĞŽƉĂƌĚ͕ ƌĞĚ ƉĂŶĚĂ͕
EĂƟŽŶĂů WĂƌŬ ĚŝƐƚƌŝĐƚ ŵƵƐŬ ĚĞĞƌ͕ ĞƚĐ͘

Times' Crucial Science and Environment 255 Book 7

ϰ͘ >ĂŶŐƚĂŶŐ EĂƟŽŶĂů ZĂƐƵǁĂ͕ ϭϳϭϬ ϮϬϯϮ ͘^͘ ZĞĚ ƉĂŶĚĂƐ͕ ŵƵƐŬ ĚĞĞƌ
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ĂƐ EĂƟŽŶĂů WĂƌŬ ũĂĐŬĂů͕ ĨŽdž͕ ĞƚĐ͘
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ǁĂƚĞƌƐŚĞĚ Θ ĚŝƐƚƌŝĐƚƐ

ǁŝůĚůŝĨĞ ƌĞƐĞƌǀĞ ŝŶ

ƚŚĞ ďĞŐŝŶŶŝŶŐͿ

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ůĞĂƉĂƌĚ͕ dŝďĞƚĂŶ͕ ŚĂƌĞ͕
EĂƟŽŶĂů WĂƌŬ ĚŝƐƚƌŝĐƚƐ
ŵƵƐŬ ĚĞĞƌ͕ ĞƚĐ͘

ϳ͘ <ŚĂƉƚĂĚ EĂƟŽŶĂů ĂũŚĂŶŐ͕ 225 ϮϬϰϮ ͘^͘ tŝůĚ ĚŽŐ͕ ǁŝůĚ ĐĂƚ͕ ŵƵƐŬ
WĂƌŬ ĂũƵƌĂ͕ ŽƟ ĂŶĚ ĚĞĞƌ͕ ďĂƌŬŝŶŐ ĚĞĞƌ͕
ĐŚŚĂŵ ĚŝƐƚƌŝĐƚƐ ůĞŽƉĂƌĚ͕ ĞƚĐ͘

ϴ͘ ĂƌĚŝLJĂ EĂƟŽŶĂů ĂƌĚŝLJĂ ĚŝƐƚƌŝĐƚ ϵϲϴ ϮϬϰϱ ͘^͘ dŝŐĞƌ͕ ďůĂĐŬ ďƵĐŬ͕ ƐƉŽƩĞĚ
WĂƌŬ ĚĞĞƌ͕ ůĞŽƉĂƌĚ͕ ďůƵĞ ďƵůů͕

ĞƚĐ͘

ϵ͘ DĂŬĂůƵ ĂƌƵŶ ^ĂŶŬŚƵǁĂƐĂďŚĂ ϭϱϬϬ ϮϬϰϵ ͘^͘ ^ŶŽǁ ůĞŽƉĂƌĚ͕ ďůĂĐŬ
EĂƟŽŶĂů WĂƌŬ Θ ^ŽůƵŬŚƵŵďƵ ďĞĂƌ͕ ĚĞĞƌ͕ ŐŚŽƌĂů͕ ĞƚĐ͘

ϭϬ͘ ĂŶŬĞ EĂƟŽŶĂů ĂŶŬĞ ϱϱϬ ϮϬϲϳ ͘^͘ tŝůĚ ĞůĞƉŚĂŶƚ͕ ůĞŽƉĂƌĚ͕
WĂƌŬ ĚĞĞƌ͕ ƟŐĞƌ͕ ǁŝůĚ ďĞĂƌ͕
ďůƵĞ ďƵůů͕ ĞƚĐ͘

ϭϭ͘ ^ŚƵŬůĂƉŚĂŶƚĂ <ĂŶĐŚĂŶƉƵƌ ϯϬϱ ϮϬϯϭ ͘^͘ ^ǁĂŵƉ ĚĞĞƌ͕ ƐƉŽƩĞĚ
EĂƟŽŶĂů WĂƌŬ ĚŝƐƚƌŝĐƚ ;ĂƐ tŝůĚůŝĨĞ ĚĞĞƌ͕ ǁŝůĚ ďŽĂƌ͕ ƐůŽƚŚ
ƌĞƐĞƌǀĞͿ ĂŶĚ ďĞĂƌ͕ ďůƵĞ ďƵůů͕ ƟŐĞƌ͕
ϭϮ͘ WĂƌƐĂ EĂƟŽŶĂů ŚŝƚǁĂŶ͕ ϲϮϳ ϮϬϳϯ ͘^͘ ;ĂƐ ǁŝůĚ ĞůĞƉŚĂŶƚ͕ ůĞŽƉĂƌĚ͕
WĂƌŬ DĂŬǁĂŶƉƵƌ͕ EĂƟŽŶĂů WĂƌŬͿ
WĂƌƐĂ ĂŶĚ ĂƌĂ ĞƚĐ͘
ĚŝƐƚƌŝĐƚƐ ϮϬϰϬ ͘^͘ tŝůĚ ĞůĞƉŚĂŶƚ͕ ƟŐĞƌ͕
;ĂƐ tŝůĚůŝĨĞ ůĞŽƉĂƌĚ͕ ƐůŽƚŚ ďĞĂƌ͕ ŐĂƵƌ͕
ƌĞƐĞƌǀĞͿ ĂŶĚ ƐƉŽƩĞĚ ĚĞĞƌ͕ ďĂƌŬŝŶŐ
ϮϬϳϯ ͘^͘ ;ĂƐ ĚĞĞƌ͕ ƐƚƌŝƉƉĞĚ ŚLJĞŶĂ͕ ĞƚĐ͘
EĂƟŽŶĂů WĂƌŬͿ

:LOGOLIH UHVHUYHV

Wildlife reserve is a separate reserved area for the protection and management
of endangered species of animals and plants. The species whose number
is decreasing and are disappearing rapidly from the world are called
endangered species. Tiger, rhino, pigmy hog, sloth bear, musk deer, red
panda, etc are some species which are listed as ‘endangered animals’.
The wildlife reserves are guarded by security forces. In these reserves, grazing

Times' Crucial Science and Environment 256 Book 7

RI GRPHVWLF DQLPDOV FXWWLQJ RI IRGGHU FXWWLQJ WLPEHU DQG ÀUHZRRG FXOWLYDWLRQ
etc are strictly prohibited. Even the tourists or visitors are not allowed to enter
the wildlife reserves. There is one wildlife reserve in Nepal.

S.N. Wildlife >ŽĐĂƟŽŶ Area Year of Main animals
ƌĞƐĞƌǀĞ (sq. km) establishment ĐŽŶƐĞƌǀĞĚ

ϭ͘ <ŽƐŚŝ dĂƉƉƵ ^ƵŶƐĂƌŝ 175 ϮϬϯϮ ͘^͘ tŝůĚ ďƵīĂůŽ ;ĂƌŶĂͿ͕ ŚŽŐ
ǁŝůĚͲůŝĨĞ ĂŶĚ ^ĂƉƚĂƌŝ ĚĞĞƌ͕ ǁŝůĚ ďŽĂƌ͕ ƐƉŽƩĞĚ
ƌĞƐĞƌǀĞ ĚŝƐƚƌŝĐƚƐ ĚĞĂƌ͕ ďůƵĞ ďƵůů͕ 'ĂŶŐĞƟĐ
ĚŽůƉŚŝŶ͕ ĐƌŽĐŽĚŝůĞ͕ ĞƚĐ͘

+XQWLQJ 5HVHUYHV

It is a separate reserved area for the conservation and management of
wildlife in which permitted hunting is allowed. The tourists or hunters
can hunt inside the hunting reserve by taking permission from concerned
authorities. The hunters have to pay certain amount of money as royalty
IRU WDNLQJ SHUPLVVLRQ $IWHU WDNLQJ SHUPLVVLRQ SDUWLFXODU DQLPDOV LQ
particular number and region can be hunted at particular time.

Dhorpatan Hunting Reserve LV WKH ÀUVW DQG RQO\ KXQWLQJ UHVHUYH LQ RXU
FRQQWU\ ,W LV ORFDWHG LQ %DJOXQJ DQG 0\JGL GLVWULFW RI 'KDXODJLUL ]RQH
DQG 5XNXP GLVWULFW RI 5DSWL ]RQH ,WV DUHD LV 1325 square kilometers. It is
attracting Nepalese and foreign hunters with blue sheep or Bharal and other
game animals. The other animals found in this reserve include Himalayan
thar, ghoral, musk deer, wild boar, wild dog, barking deer, red panda, etc.

:LOGOLIH &RQVHUYDWLRQ $UHDV

These are the conserved areas with the participation of local people. In these
areas, the plants and animals are conserved in their natural environment.
3HRSOH FDQ REWDLQ IRGGHU ÀUHZRRG GU\ OHDYHV HWF IURP WKH FRQVHUYDWLRQ
DUHD WKURXJK D FRQVXPHU FRPPLWWHH 7KHUH DUH VL[ ZLOGOLIH FRQVHUYDWLRQ
areas in Nepal. Some of them are given below.

S.N. Wildlife Area Date of >ŽĐĂƟŽŶ
ŽŶƐĞƌǀĂƟŽŶ ĂƌĞĂ (sq. km) establishment
<ĂƐŬŝ͕ >ĂŵũƵŶŐ͕ DLJĂŐĚŝ͕ DƵƐƚĂŶŐ ĂŶĚ
ϭ͘ ŶŶĂƉƵƌŶĂ ǁŝůĚůŝĨĞ ϳϲϮϵ ϮϬϰϵ ͘^͘ DĂŶĂŶŐ ĚŝƐƚƌŝĐƚƐ
ĐŽŶƐĞƌǀĂƟŽŶ ĂƌĞĂ
dĂƉůĞũƵŶŐ ĚŝƐƚƌŝĐƚ ;DĞĐŚŝ njŽŶĞͿ
Ϯ͘ <ĂŶĐŚĂŶũĂŶŐŚĂ ǁŝůĚůŝĨĞ ϮϬϯϱ ϮϬϱϰ ͘^͘
ĐŽŶƐĞƌǀĂƟŽŶ ĂƌĞĂ EŽƌƚŚĞƌŶ ƉĂƌƚ ŽĨ 'ŽƌŬŚĂ ĚŝƐƚƌŝĐƚ

ϯ͘ DĂŶĂƐůƵ tŝůĚůŝĨĞ ϭϲϲϯ ϮϬϱϱ ͘^͘
ŽŶƐĞƌǀĂƟŽŶ ƌĞĂ

Times' Crucial Science and Environment 257 Book 7

Some of the protected animals in national parks, wildlife reserves and
conservation areas are given below:

,PSRUWDQFH RI QDWLRQDO SDUNV DQG ZLOGOLIH UHVHUYHV

1. These areas conserve the wildlife together with their natural
environment.

2. They protect natural scenery, water resources and natural heritages.
7KHVH DUHDV KHOS WR FRQWURO VRLO HURVLRQ ÁRRG DQG ODQGVOLGHV
4. These are the best places for entertainment.
7KH\ DUH XVHIXO IRU VFLHQWLÀF VWXGLHV DQG UHVHDUFKHV
6. They provide employment to the people.
7. They help to increase the revenue of the country as the tourists

spend money while visiting these areas, hunting, etc.

:DWHU UHVRXUFH

Water is one of the important
natural resources. It is used for
several purposes. In fact, life is
impossible without water. In our
country water is obtained from
different sources such as springs,
lakes, melting of snow from high
Himalayas, etc. The melted snow
is one of the main sources of water
ÁRZLQJ LQ WKH ULYHUV
The importance of water resource can be summarized in following points:

1. They are the sources of water for a number of purposes.

Times' Crucial Science and Environment 258 Book 7

2. They are the shelters for a large number of aquatic lives.
3. They help to conserve forest areas and natural beauty.
4. They can be used for agricultural purposes and for generating

hydroelectricity.
5. They help to conserve biodiversity and maintain the balance in

nature.
6. They help to improve the economic condition of a nation by promoting

tourism.
7. They can support the lives of local people if they are managed

properly.

&RQVHUYDWLRQ RI ZDWHU UHVRXUFH

The rapid population growth and the increase in human needs have
resulted in the depletion of the sources of water. So, these sources must
EH FRQVHUYHG IRU WKHLU HIÀFLHQW DQG ORQJ WHUP XVH 6RPH PHDVXUHV IRU WKH
conservation of water resource are as follows:

1. The best way for the conservation of wetlands and watersheds is
afforestation. The forest plays very important role in water cycle
and it also helps to hold water in the earth’s crust.

2. Public awareness is an important measure for the conservation of
watersheds and wetlands. Local people can take necessary steps for
the conservation and promotion of the water resources.

3. Construction of check dams helps to reduce the speed of running
water and thus helps to control soil erosion.

4. Control of water pollution helps to preserve the natural quality of
water and maintains environmental balance.

:DWHUVKHG

The runoff water from particular slopes and areas of land is collected in
the rivers, streams, wells, lakes, etc of that area. Such areas are known as
watersheds. Hence, the area of land around any source of water is known
DV ZDWHUVKHG )RU H[DPSOH WKH VORSS\ DQG KLOO\ UHJLRQ LQ WKH QRUWK RI WKH
Kathmandu valley is the watershed for the valley. The rain water absorbed
and collected in the areas of Shivapuri National Park and its neighbouring
slopes is the source of water for Bagmati and Bishnumati rivers, other
streams and underground water in the Kathmandu valley. Similarly,
the southern slope of the southern hills of the Kathmandu valley forms
WKH .XOHNKDQL ZDWHUVKHG RI WKH 0DNDZDQSXU GLVWULFW 7KH ,QGUDVDURZDU
receives and collects water from this region. The Indrasarowar is the

Times' Crucial Science and Environment 259 Book 7

largest manmade lake of Nepal. On the other hand, the area around the
Phewa Lake is the Phewa Lake watershed.

Koshi, Gandaki and Karnali are the large watersheds of Nepal. There are
thousands of other smaller watersheds in Nepal.

Importance of watershed

7KH ZDWHUVKHGV IXOÀOO WKH ZDWHU UHTXLUHPHQWV RI KXPDQ EHLQJV RWKHU
DQLPDOV DQG SODQWV RI QHDUE\ DUHDV 7KH ZDWHUVKHGV KDYH D VLJQLÀFDQW
role in the development and conservation of forests. They help to conserve
agricultural land and to increase productivity. The watersheds are the
important factors for the balance in nature.

Conservation of watersheds

+XPDQ EHLQJV DUH ODUJHO\ H[SORLWLQJ WKH QDWXUDO UHVRXUFHV IRU IXOÀOOLQJ
their needs. The overpopulation has resulted in deforestation, overuse of
resources, drying of small sources of water, etc. Hence, it is necessary to
conserve and promote the watersheds. Conservation of forest, afforestation,
terrace improvement, check dams and embankments in the rivers, public
awareness, etc are some measures to conserve watersheds.

Wetlands

In general, wetland is the area of land which is covered by water round
WKH \HDU ,W LQFOXGHV WKH PXGG\ DQG PDUVK\ DUHDV ZLWK H[FHVV ZDWHU 7KH
ZHWODQG LV GHÀQHG DV WKH DUHD RI ZDWHU\ PXGG\ RU PDUVK\ ODQG LQ ZKLFK
WKH GHSWK RI ZDWHU LV OHVV WKDQ PHWHUV .RVKL 7DSSX :LOGOLIH 5HVHUYH LV
WKH ÀUVW WR EH LQFOXGHG LQ WKH OLVW RI :RUOG :HWODQG $UHDV $FFRUGLQJ WR
the study conducted by World Conservation Union (IUCN), there are 163
wetlands in Terai, 164 wetlands in hill and 78 wetlands in the mountain
region of Nepal. There are a number of glacial lakes, lakes, ponds, streams,
brooks, marshy areas, muddy lands, etc in Nepal. Hence, Nepal is rich in
wetlands and water resources.

Importance of wetlands

:HWODQG LV YHU\ EHQHÀFLDO IRU DJULFXOWXUH

2. It is the favourable place for the shelter of birds.

3. It helps to maintain the balance in nature.

4. It provides water and shelter to a large number of organisms.

7KH ZHWODQGV FDQ EH XWLOL]HG IRU WKH ÀVK IDUPLQJ DQG RWKHU
purposes.

6. Wetlands are also important from tourism point of view.

Times' Crucial Science and Environment 260 Book 7

&RQVHUYDWLRQ RI ZHWODQGV

0DQ\ KXPDQ DFWLYLWLHV DUH UHVSRQVLEOH IRU WKH GHVWUXFWLRQ RI WKH ZHWODQGV
2YHU H[SORLWDWLRQ RI ZDWHU IURP WKH ZHWODQGV GU\LQJ RI ZHWODQGV IRU
agriculture and settlement, establishing industries, throwing wastes and
polluting them, etc are destroying the wetlands. Hence, it is necessary to
take effective steps for the conservation of wetlands.
The International Conference for the Conservation of Wetlands held in
5DPVDDU RI ,UDQ LQ $' KDV SDVVHG D FRQYHQWLRQ 7KLV FRQYHQWLRQ LV
NQRZQ DV 5DPVDDU &RQYHQWLRQ 7KLV FRQYHQWLRQ KDV XUJHG HYHU\ QDWLRQ WR
SURWHFW DQG SURPRWH WKH ZHWODQGV .RVKL 7DSSX :LOGOLIH 5HVHUYH %LV +DMDUL
7DO &KLWZDQ -DJGLVKSXU -DODVKD\D .DSLOYDVWX DQG *KRGD *KRGL 7DO
(Kailali) are the wetlands of Nepal to be included in the list of Wetlands of
International Importance.

%DODQFH LQ 1DWXUH

The balance in nature is maintained by two major components- abiotic
components and biotic components. The non-living components of the
HQYLURQPHQW DUH FDOOHG DELRWLF FRPSRQHQWV $LU ZDWHU VRLO WHPSHUDWXUH
sunlight, etc are the abiotic components of the environment. Similarly,
the living components of the environment are called biotic components. For
H[DPSOH DOO DQLPDOV SODQWV DQG PLFUR RUJDQLVPV DUH ELRWLF FRPSRQHQWV
Both biotic and abiotic components of the environment are mutually
GHSHQGHQW RQ HDFK RWKHU IRU WKHLU H[LVWHQFH The interrelationship between
the biotic and abiotic components of an environment is called ecosystem.

lion vulture leopard

baboon

rhino African impala
JLUDႇH skunk snake
¿VFDO
shrike

caracal

grasshopper mouse

tree shrub

Times' Crucial Science and Environment grass Book 7

261

%LRWLF &RPSRQHQWV

The biotic components can be divided into three types- producers, consumers
and decomposers.
1. Producers
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the presence of sun light. Thus produced food is the source of energy for
all animals and the plants themselves. So, the plants are called producers.
2. Consumers
The organisms that depend on the foods prepared by the green plants are
called consumers. The consumers are of three types- primary consumers,
secondary consumers and tertiary consumers.
The animals which feed on the plants only are called primary consumers.
)RU H[DPSOH WKH KHUELYRURXV DQLPDOV DUH SULPDU\ FRQVXPHUV 7KH DQLPDOV
which feed on primary consumers are called secondary consumers. For
H[DPSOH MDFNDO WLJHU HWF DUH VHFRQGDU\ FRQVXPHUV The animals which
feed on secondary consumers are called tertiary consumers. )RU H[DPSOH
snake is a tertiary consumer.

Grass *UDVVKRSSHU )URJ 6QDNH
(Producer) (Tertiary consumer)
(Primary consumer) (Secondary consumer)

Producer Primary consumer Secondary consumer

3. Decomposers

The organisms which decompose the dead bodies of plants and animals to
produce nutrients for the producers are called decomposers. Bacteria and
fungi are the decomposers.

Times' Crucial Science and Environment 262 Book 7

Each component of the environment is equally important. The biotic
components of the ecosystem depend on abiotic components on many
respects. Similarly, the abiotic components also depend on biotic
FRPSRQHQWV )RU H[DPSOH DOO OLYLQJ RUJDQLVPV ELRWLF FRPSRQHQWV XVH
R[\JHQ DELRWLF FRPSRQHQW IRU EUHDWKLQJ 2Q WKH RWKHU KDQG R[\JHQ LV
produced by the green plants during photosynthesis. Thus, there is balance
LQ WKH DPRXQW RI R[\JHQ LQ WKH DWPRVSKHUH

ŝŽĚŝǀĞƌƐŝƚLJ ͗ ǀĂƌŝĞƟĞƐ ŽĨ ĂŶŝŵĂůƐ ĂŶĚ ƉůĂŶƚƐ ŝŶ ƚŚĞ ĞĂƌƚŚ

tŝůĚůŝĨĞ ͗ ǁŝůĚ ĂŶŝŵĂůƐ ĐŽůůĞĐƟǀĞůLJ

īŽƌĞƐƚĂƟŽŶ ͗ ĞƐƚĂďůŝƐŚŵĞŶƚ ŽĨ ĨŽƌĞƐƚ

&ŽĚĚĞƌ ͗ ĚƌŝĞĚ ĨŽŽĚƐ Žƌ ƉůĂŶƚƐ ĨŽƌ ĐĂƩůĞ

ZŽLJĂůƚLJ ͗ Ă ƐƵŵ ƉĂŝĚ ĨŽƌ ƵƐĞ ŽĨ ƉƵďůŝĐ ƉƌŽƉĞƌƚLJ

&ůŽƌĂ ͗ ƉůĂŶƚƐ ŽĨ Ă ƉĂƌƟĐƵůĂƌ ƌĞŐŝŽŶ

&ĂƵŶĂ ͗ ĂŶŝŵĂůƐ ŽĨ Ă ƉĂƌƟĐƵůĂƌ ƌĞŐŝŽŶ

WƌŽŚŝďŝƟŽŶ ͗ ĂĐƚ ŽĨ ƐƚŽƉƉŝŶŐ Žƌ ďĂŶŶŝŶŐ

0DLQ 3RLQWV WR 5HPHPEHU

1. The useful substances found naturally on the earth are known as
natural resources.

2. The natural resources can be divided into three types- renewable,
non-renewable and perpetual natural resources.

3. Forest, wildlife, watersheds, etc are the natural heritages.

$ QDWLRQDO SDUN LV D VHSDUDWH SLHFH RI ODQG SURWHFWHG IRU WKH SURSHU
management and conservation of wildlife together with their
natural environment.

5. Wildlife reserve is a separate reserved area for the protection and
management of endangered species of plants and animals.

6. Hunting reserve is a separate reserved area for the conservation
and management of wildlife in which permitted hunting is allowed.

7. The region which is always wet with water and contains water in
H[FHVV DPRXQW LV FDOOHG ZHWODQG

8. The watersheds are the natural sources of water from where water
runs in different directions to meet different rivers.

9. The balance in nature is maintained by two major components -
biotic components and abiotic components.

Times' Crucial Science and Environment 263 Book 7

7KH LQWHUUHODWLRQVKLS EHWZHHQ ELRWLF DQG DELRWLF FRPSRQHQWV RI DQ
environment is called ecosystem.

([HUFLVH

1. Choose the best alternative in each case.

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i. Water ii. Forest

iii. Solar energy iv. Petroleum

b. The organisms which prepare their own food themselves are
called

i. Herbivores ii. Consumers

iii. Decomposers iv. Producers

F :KLFK LV WKH ROGHVW QDWLRQDO SDUN RI 1HSDO"
i. Bardiya National Park
ii. Chitwan National Park

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iv. Sagarmatha National Park

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i. Khaptad National Park
ii. Shey-Phoksundo National Park
iii. Bardiya National Park

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H :KLFK RI WKH IROORZLQJ DQLPDOV LV OLVWHG DV HQGDQJHUHG DQLPDO"

i. Spotted deer ii. Crocodile

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2. Answer these questions in very short.
D :KDW DUH QDWXUDO UHVRXUFHV "
E *LYH DQ H[DPSOH RI SHUSHWXDO QDWXUDO UHVRXUFH
F :KDW LV WKH WRWDO DUHD RI &KLWZDQ 1DWLRQDO 3DUN "
G :KLFK LV WKH ELJJHVW QDWLRQDO SDUN RI 1HSDO " :KDW LV LWV DUHD "
e. Write down the name and area of smallest national park of Nepal.

Times' Crucial Science and Environment 264 Book 7

I :KLFK QDWLRQDO SDUN OLHV QHDUHVW WR WKH FDSLWDO FLW\ RI 1HSDO "
J :KHUH LV ZLOG EXIIDOR IRXQG LQ 1HSDO "
K :KDW LV WKH WRWDO DUHD RI 'KRUSDWDQ +XQWLQJ 5HVHUYH "
L :KHUH LV 0DQDVOX :LOGOLYH &RQVHUYDWLRQ $UHD ORFDWHG "
M *LYH DQ\ WZR H[DPSOHV RI DELRWLF FRPSRQHQWV RI DQ HFRV\VWHP

3. Write down differences between:
D 5HQHZDEOH DQG QRQ UHQHZDEOH QDWXUDO UHVRXUFHV
b. National park and wildlife reserves
c. Wetland and watershed
d. Producer and consumer

4. Give reasons:
a. Forest is a renewable natural resource.
b. Petrol, diesel and kerosene are non-renewable natural resources.
F $IIRUHVWDWLRQ LV KHOSIXO WR FRQVHUYH ZHWODQGV DQG ZDWHUVKHGV

5. Answer these questions:
D ([SODLQ WKH GLIIHUHQW W\SHV RI QDWXUDO UHVRXUFHV
b. Enlist the importance of natural resources.
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Nepal with their area.
G 'HÀQH ZLOGOLIH UHVHUYH (QOLVW GLIIHUHQW ZLOGOLIH UHVHUYHV RI 1HSDO
e. Write down the importance of water resources.
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J :KDW DUH FRQVXPHUV" 'HÀQH GLIIHUHQW W\SHV RI FRQVXPHUV ZLWK
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Draw a full page map of Nepal in a chart paper and locate the National
3DUNV :LOGOLIH 5HVHUYHV DQG :LOGOLIH &RQVHUYDWLRQ $UHDV ZLWK WKHLU
areas. Show your work to your teacher.

Times' Crucial Science and Environment 265 Book 7

Chapter ( QYLURQPHQWDO
' HJUDGDWLRQ DQG LWV
25
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OBJECTIVES

At the end of the lesson, the students will be able to :
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(QYLURQPHQWDO GHJUDGDWLRQ

There are different types of natural resources around us. Land, forest,
lakes, ponds, rivers, air, hills, mountains, natural beauty, birds, animals,
etc are some natural resources.

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needs. They use land for cultivation, construction of roads, buildings,
settlement, and deposition of waste materials. They use water for irrigation,
drinking, cleaning, swimming, boating, etc. In the same way, birds and
animals are used by human beings for entertainment, meat, leather,
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Population is increasing rapidly. Due to this, their needs and wants are
also increasing. They are using the natural resources haphazardly.

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They are destroyed to get the land for cultivation and human settlement.
9DULRXV W\SHV RI DQLPDOV DQG ELUGV DUH EHLQJ GHVWUR\HG IRU IXOÀOOLQJ

Times' Crucial Science and Environment 266 Book 7

KXPDQ QHHGV DQG GHVLUHV 0DQ\ DQLPDOV DUH LQ WKH ZD\ WR EH H[WLQFW 'XH
WR WKH RYHUXVH DQG H[SORLWDWLRQ RI ZDWHU UHVRXUFHV VXFK DV ODNHV SRQGV
rivers, streams, etc, they are getting dried and polluted. Various types of
LQGXVWULDO FKHPLFDOV VROLG ZDVWHV DQG VHZDJHV DUH PL[HG WR WKH ZDWHU
UHVRXUFHV FDUHOHVVO\ 7KH ODQG LV EHLQJ SROOXWHG GXH WR PL[LQJ RI YDULRXV
types of chemicals, garbages, faeces, etc to the land. These activities cause
environmental degradation.

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WKH QDWXUDO UHVRXUFHV KDSKD]DUGO\ DQG H[FHVVLYHO\ ZKLFK FDXVH WKH
degradation in the quality and quantity of the various components of the
environment.

There are various causes for environmental degradation. Some of them are
as follows:

i. Destruction of natural resources

ii. Urbanization and Industrialization

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a) Deforestation

Forest and forest products are bases of living things. Forest provides
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provides shelter to wild animals and birds. But, forest is being destroyed
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IRU ÀUHZRRG WLPEHU JUDVV HWF 7KH\ DUH GHVWUR\LQJ WKH IRUHVW IRU JHWWLQJ
the land for cultivation and human settlement.

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human being is called deforestation.

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Following are the causes of deforestation

a. Cutting down the trees
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timber, grass, fodder etc.

b. Destroying forest for getting
land for cultivation and
human settlement.

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of saplings and plants.

d. Overgrazing causes destruction
of plants which leads to deforestation.

Times' Crucial Science and Environment 267 Book 7

(൵HFWV RI GHIRUHVWDWLRQ

a. Deforestation causes the loss of shelter of wild animals.
b. Sources of water get dried.
c. Low rainfall occurs.
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The activities to be done to prevent deforestation are as follows:
i) The cutting down of the trees should be discouraged.
ii) Saplings should be planted in naked hills.
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LY )RUHVW ÀUH VKRXOG EH SUHYHQWHG )RU WKLV DZDUHQHVV VKRXOG EH
provided to the people. Cigarette butt should not be thrown carelessly.
v) People should be made aware about the importance of forest.
vi) Strict laws should be made and implemented against deforestation.
vii) Population growth should be controlled.

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b. Water Pollution (Degradation of water resources)
Water is one of the important natural resources. It is used by human beings
for drinking, irrigation, industrial works, recreation, transportation,
production of hydroelectricity, etc. Water is used by the plants for the
preparation of foods. Water provides shelter to various types of aquatic
animals. Various types of aquatic plants grow in water.
We get water from rivers, ponds, lakes, stream, rain, underground source,
etc. Nepal is the second richest country in water resources. There are
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rivers and streams depend upon rainfall. There are many lakes in our
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water is soaked through the soil and gets collected under the ground, it is

Times' Crucial Science and Environment 268 Book 7

considered as underground water. Water from well, tube well, spring etc
are underground water.
Various human activities cause the degradation of water resources. They are:

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0L[LQJ VHZDJHV ZDVWHV IURP WRLOHW DQG NLWFKHQ WR WKH ZDWHU
3. Bathing and cleaning clothes and utensils near the source of water.
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([FHVVLYH XVH RI LQVHFWLFLGHV DQG FKHPLFDO IHUWLOL]HUV
6. Spilling of petroleum oil while transporting through ocean.

Effects of water pollution

1. Polluted water causes various types of diseases like dysentery,
diarrhoea, jaundice, typhoid, cholera, etc.

2. Polluted water causes various types of diseases in aquatic animals.

3. Plants cannot grow well in polluted water.

4. Polluted water causes air pollution, too.

5. Bad smell coming from polluted water disturbs concentration and
working of people.

Measures to control water pollution

1. Bathing and cleaning clothes and utensils near the source of water
should be avoided.

2. The chemicals and wastes produced from factories and industries
VKRXOG EH WUHDWHG DQG UHÀQHG EHIRUH PL[LQJ WR WKH ULYHU ODNHV RU
oceans.

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of water.

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avoided.

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sources of water will not be polluted.

6. People should be made aware about the bad impacts of water
pollution.

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avoided.

Times' Crucial Science and Environment 269 Book 7

c) Land Pollution

Land is one of the important natural resources. It is natural habitat for all
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Various types of small animals like insects, mice, snake, etc live under
the ground. Human beings carry out construction works on the land. They
make buildings, roads, parks, playground, etc on the land. It is used for
cultivation too. Thus, land is very important for plants and animals. But,
it is being polluted due to various types of human activities.

Causes of land pollution

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E ([FHVVLYH XVH RI LQVHFWLFLGHV DQG SHVWLFLGHV

c. Throwing of non-decaying materials like plastic, metal pieces,
broken glasses, etc to the land.

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H 7KURZLQJ RI FDWWOH H[FUHWD ZDVWHV IURP KRXVHV HWF WR WKH VRLO

f. Dumping of wastes from kitchen and houses on the land.

Effects of land pollution

1. Plants cannot grow well in polluted soil.

2. Crops grown in polluted land are poisonous. Such crops make human
beings sick.

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4. Bad smell coming from the polluted soil affects the surroundings.

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can transmit various types of diseases.

6. The use of chemical fertilizers and insecticides causes an adverse
effect on the health of man, animals and plants.

7. The soil pollution decreases beauty of the environment.

Measures to control land pollution
1. Insecticides and chemical fertilizers should be used properly.
2. Non-biodegradable things like plastic, rubber, metal, glass bottles,
etc should be reused.
%LR GHJUDGDEOH WKLQJV OLNH H[FHVV IRRG SHHOV RI IUXLWV DQG YHJHWDEOHV
cattle dung, etc should be used to prepare compost manure.

Times' Crucial Science and Environment 270 Book 7

4. Chemicals and wastes from factories and industries should be
WUHDWHG EHIRUH PL[LQJ WR WKH ODQG

5. Non-biodegradable goods should be recycled and reused.

d) Air Pollution
$OO OLYLQJ WKLQJV QHHG R[\JHQ WR VXUYLYH 7KH\ JHW R[\JHQ IURP DWPRVSKHUH
1R DQ\ OLYLQJ WKLQJ FDQ VXUYLYH ZLWKRXW R[\JHQ 7KHUHIRUH LW LV FDOOHG life
gas 3ODQWV DOVR QHHG R[\JHQ IRU UHVSLUDWLRQ 7KH\ XVH FDUERQ GLR[LGH IRU
WKH SUHSDUDWLRQ RI IRRG GXULQJ SKRWRV\QWKHVLV $LU LV XVHG IRU EXUQLQJ IXHOV
too. Thus, air is very important. But air is being polluted due to different
human activities.
Some of such activities are as follows:

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plastic, etc.

2. Smoke and dust produced from factories.

3. Dust produced from running vehicles and construction of roads or
buildings.

4. Bad smell coming from dead and decayed things deposited near
house or roads.

Effects of air pollution

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as common cold, pneumonia, bronchitis, lung cancer, etc.

2. Dust and smoke cause warming of the earth. It is called global
warming which affects the whole climatic activities.

3. Polluted air destroys the cultural heritages like temples, monuments,
monasteries, etc.

4. It causes acid rain.

5. Dust particles collected in the leaves of plants reduce the rate of
photosynthesis.

Control measures of air pollution

1. Tree plantation should be done nearby the houses and roads.

2. The engines of vehicles and factories should be maintained so that
they produce less smoke.

3. The factories and industries should be located far away from human
settlement.

Times' Crucial Science and Environment 271 Book 7

4. Solar heater, electricity, L.P. gas, etc should be used in cooking
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5. Legal arrangements should be made to control the air pollution

e) Overuse of minerals
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earth. They are found in the mines. Iron, copper, gold, diesel, coal, petrol,
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We use minerals like iron, copper, gold, etc for coins, utensils, wires,
machineries, etc. We use iron for the construction of buildings, bridges, etc.
We use petrol, diesel, coal, etc as fuel for cooking foods, running vehicles
and machineries. Various types of minerals are used by the plants for the
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WKHP FDUHOHVVO\ WKHLU VWRFN ZLOO EH ÀQLVKHG
Following are the causes of destruction of minerals.

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wires, machineries, buildings, etc.

LL ([FHVVLYH XVH RI SHWURO GLHVHO FRDO HWF DV IXHO

Conservation of minerals
Following activities are done to conserve minerals:

i) Electricity, solar energy, bio-gas, etc should be used instead of petrol,
diesel and coal.

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LLL ([WUDFWLRQ RI PLQHUDOV IURP WKH PLQH VKRXOG EH PLQLPL]HG

Destruction of Wildlife
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RI LQVHFWV VSHFLHV RI ÀVKHV VSHFLHV RI DPSKLELDQV VSHFLHV RI
UHSWLOHV VSHFLHV RI ELUGV DQG VSHFLHV RI PDPPDO DUH IRXQG 0RVW RI
them live in forest. Due to deforestation, their habitats are destroyed and
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IR[ ZLOG EXIIDOR KRUQELOO S\WKRQ HWF IDOO XQGHU HQGDQJHUHG VSHFLHV

Times' Crucial Science and Environment 272 Book 7

Following are the causes for the destruction of wildlife:
i) Destruction of forest which is the natural habitat of wildlife.
ii) Hunting of the wild animals.
iii) Pollution of water, air, land, etc causes the destruction of wildlife.
iv) Use of pesticides and insecticides causes the destruction of wildlife.

Effects of destruction of wildlife
1. Destruction of wildlife causes the ecological imbalance.
2. Destruction of wildlife decreases natural beauty. Due to this, tourism
industry is affected.
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production decreases.

Conservation of wildlife
1. Strict laws are to be made and implemented against killing of
wildlife.
2. Tree plantation programmes are to be launched.
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among the people.

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a) Urbanization
Urbanization means the development of urban areas and the increment
of total population residing in urban areas. The urban areas of a country
are the areas where the houses and buildings are crowded, markets are
available, various facilities such as transportation, communication, health
services, education, recreation, etc are available. The urban areas of a
FRXQWU\ DUH LGHQWLÀHG DV PXQLFLSDOLW\ VXE PHWURSROLWDQ PHWURSROLWDQ
city area, headquarters, etc. But, the rural areas are the areas where the
facilities of transportation, communication, health, education, market, etc
are not available.

People of rural areas want to move towards urban areas to get various
facilities. They want to convert the rural areas into urban areas. In this
process many villages are converting into cities.
When urbanization is done in a planned way, it does not affect the
environment adversely. But, unplanned urbanization causes various types
of environmental problems.
Some adverse effects of urbanization are as follows:

Times' Crucial Science and Environment 273 Book 7

1. Due to crowd of buildings and more population, there is lack of
proper place for solid waste management. Solid wastes are dumped
or scattered near the roads or houses. It causes land pollution.

0RUH QXPEHU RI YHKLFOHV DUH XVHG LQ XUEDQ DUHDV 9HKLFOHV SURGXFH
too much smoke and dust which make the air polluted.

3. Due to population pressure, there may be lack of employment
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there might be robbery, theft, blackmailing, murdering, etc. Thus, it
creates unhealthy social environment.

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water pollution.

5. Sound produced from the vehicles and crowd of the people causes
noise pollution.

b) Industrialization
Industrialization is a process of establishing various types of industries and
development of industrial areas. Industrial development is very important
for the development of nation. But, unmanaged industrial development
affects the environment adversely. Some effects are as follows:

0RVW RI WKH LQGXVWULHV SURGXFH VPRNH DQG GXVW 7KH\ FDXVH DLU
pollution.

2. The dust and black smoke damage the physical environment and
destroy natural beauty.

3. The chemicals and wastes produced from the industries pollute
water and land.

4. Industries use various types of natural resources like minerals,
forest products, petroleum, etc. It may cause over consumption of
resources.

7KH KDUPIXO JDVHV OLNH VXOSKXU GLR[LGH SURGXFHG IURP WKH LQGXVWULHV
cause acid rain.

Times' Crucial Science and Environment 274 Book 7

1DWXUDO 'LVDVWHUV

The natural activities which cause the damage of natural resources, man
made constructions and lives of animals are called natural disasters.
(DUWKTXDNH ÁRRG ÀUH ODQGVOLGH YROFDQR HWF DUH VRPH RI WKH QDWXUDO
disasters, which occur frequently in different parts of the world. They
cause the damage of infrastructures of development, buildings, lives of
animals, etc.

Earthquake
The sudden shaking or vibration of the earth surface is called earthquake. It
is devastating natural disaster. It causes the destruction of buildings and
man-made structures. The earthquake affects the environment adversely.

Some of the effects are as follows.
1. It causes the damage of the man-made structures such as buildings,
dams, bridges, roads, etc. Destruction of these structures may kill
many animals and deposit debris on the lands causing land, air and
water pollution
,W GDPDJHV QDWXUDO VWUXFWXUHV DQG FDXVHV ODQGVOLGH 0DQ\ DQLPDOV
will be killed and vegetation will be destroyed. The falling of soil and
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ULYHU DQG PD\ FDXVH ÁRRG ODWHU

Preventive measures against earthquake
Earthquake is a natural disaster. So, it cannot be stopped but its effects
can be minimized by using some methods:

i) Earthquake resistant buildings, dams, roads, bridges, etc should be made.
ii) If we are outside the house, we have to move towards open area.
iii) If we are inside the house, we have to protect our life by hiding

under the table or chairs.

Times' Crucial Science and Environment 275 Book 7

iv) Public awareness should be provided relating to preventive measures
of the earthquake.

Volcano
Volcano is a vent on the earth’s surface
from where hot molten substance, hot
gases, etc come out with a great force.
Inside the earth, there is hot molten
substance called magma. The magma
is under high pressure and tries to
FRPH WR WKH VXUIDFH :KHQ LW ÀQGV
weak part, it comes to the surface of
the earth with great force. The process
is called volcanic eruption.
It affects the environment and human beings in following ways:

i) It destroys the natural vegetation and animals.
ii) It destroys the man-made structures such as buildings, dams,

bridges, etc.
iii) Hot magma erupted in large quantity may cover fertile land and

convert it to barren land.
iv) It may cause rise in temperature of the earth.
v) It causes landslide and earthquake.

Safety measures
Volcanic eruption is a natural process. It cannot be stopped but its effects
can be minimized by the following methods.

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should not be made in such areas.

2. It may cause landslide and earthquake. Safety measures of landslide
and earthquake should be done.

3. Public awareness should be generated about the risks of volcano
and its area.

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The main causes of environmental pollution are the wastes which are
SURGXFHG IURP KRXVHV KRVSLWDOV LQGXVWULHV VFKRROV RIÀFHV EXVLQHVV
centers, etc. The wastes may be solid, liquid or gases. Dust, ash, waste
papers, broken glasses, plastic bags, pieces of metals, remaining vegetable

Times' Crucial Science and Environment 276 Book 7

and foods, etc are solid wastes. The waste liquids from kitchen, toilet,
industries, hospitals, etc are some liquid wastes. The smoke, dust, harmful
gases produced from houses, laboratories, industries, etc are some gaseous
wastes.

Cleanliness of the environment can be easily carried out when the wastes
are managed properly. The management of wastes contain three aspects:
reduction, reuse and recycle.

5HGXFWLRQ

The production of the wastes should be reduced as
far as possible. The wastes from kitchen should be
minimized. The foods prepared should not be more than
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and fruits should be eaten. The production of wastes
from industries should be reduced. Use of environment
pollutants like polythene bags, chemicals, metal cans, etc
VKRXOG EH PLQLPL]HG 7KH ZDVWHV VKRXOG EH FODVVLÀHG LQWR ELRGHJUDGDEOH
and non-biodegradable. Biodegradable wastes should be decomposed to
prepare compost manure, whereas the non-biodegradable wastes should
be reused.

5HXVH

The non-biodegradable solid wastes should not be thrown. They should be
used again. The plastic and glass bottles, metal cans, polythene bags and
other materials should be reused we can keep food grains, spices, etc in
metal or plastic cans of horlicks, boost, etc.

5HF\FOH

Some of the solid wastes are non-biodegradable and do not get decomposed.
They should be collected separately in a separate bin. They should be
recycled in industries. Plastic and polythene wastes should be recycled
to produce new products. The wastes from woods or bamboos should be
recycled to make papers. The glass pieces should be recycled to make new
glass products. The waste papers can be recycled to produce new paper
products. The rubber pieces can be recycled to get new type of rubber
products.

/RFDO SUDFWLFHV IRU HQYLURQPHQW FRQVHUYDWLRQ

(QYLURQPHQW FRQVHUYDWLRQ FDQ EH GHÀQHG DV DOO WKRVH DFWLYLWLHV ZKLFK DUH
conducted for the preservation of all the components of the environment. Local

Times' Crucial Science and Environment 277 Book 7

people should play important roles for the conservation of environment.
Some of the major practices of environment conservation are as follows:

a) Conservation of forest
Local people are participating actively for the conservation of forest.
Community forest (Samudayik Ban) is being made by the participation of
local people. They take responsibility to manage and preserve such forest.
Local people are made aware about the importance of forest by awareness
programmes launched in different occasions. Various conservation agencies
are working in local level, too.

b) Soil conservation
Local people are participating actively for soil conservation. Side dams are
made in the rivers. Tree plantations are done near the banks of rivers.
Terrace farming is done in the sloppy land. Tree plantation is done in
naked hills. Various awareness programmes are launched to make the
local people aware about the conservation of soil.

c) Management of wastes
Various organizations and local bodies are involved for the management of
wastes. People are encouraged to make latrines. Public latrines are made
to manage wastes. The local people are made educated about the use of the
biodegradable wastes to prepare compost manure.
d) Control of pollutants
Local people are aware about the release of pollutants. Waste water,
dust particles, garbage, harmful chemicals released from the hospitals,
LQGXVWULHV HWF DUH WUHDWHG EHIRUH PL[LQJ WKHP WR WKH ZDWHU VRXUFHV 7KH
awareness to the people about the use of chemical fertilizers and pesticides
is being done.
e) Water conservation
Water is the basis for the survival of animals and plants. It is essential for
ecological balance also. It is equally important for tourism development.
Local people are taking part actively for water conservation. They dig
SRQGV DQG VWRUH ZDWHU LQ WKH SRQG IRU ÀVK IDUPLQJ 7KH\ FROOHFW ZDWHU IURP
the springs for drinking and irrigation.

Some Government and non-government agencies for the
conservation of environment
Various governmental and non-governmental organizations are working
LQ WKH ÀHOG RI FRQVHUYDWLRQ RI HQYLURQPHQW 6RPH RI WKHP DUH DV IROORZV

Times' Crucial Science and Environment 278 Book 7

a) Ministry of Forest and Land Conservation
,W LV D JRYHUQPHQW DJHQF\ 0LQLVWU\ RI IRUHVW DQG ODQG FRQVHUYDWLRQ
LV ZRUNLQJ LQ WKH ÀHOG RI FRQVHUYDWLRQ RI IRUHVW DQG ODQG $IIRUHVWDWLRQ
programme, community forest programme, etc are launched by it.

b) Ministry of Environment and Science
7KLV PLQLVWU\ LV ZRUNLQJ LQ WKH ÀHOG RI HQYLURQPHQW FRQVHUYDWLRQ ,W FRQWUROV
the activities which degrade the environment. It determines the standards
for the various activities and provide to the concerned monitoring bodies
for implementation.

c) Ministry of Education and Sports
It is a government agency. Curriculum Development Centre (CDC) which
works under this ministry prepares curriculum for schools. The students study
WKH WH[W ERRNV SUHSDUHG RQ WKH EDVLV RI FXUULFXOXP DQG LQYROYH LQ HQYLURQPHQW
conservation programmes. Subject matters of environmental conservation
and natural resource conservation are taught in schools and colleges.
d) Local Level Non-government Organizations
Various local level non-government organizations are established for the
environmental conservation. They carry out tree plantation programme,
conservation of biodiversity, water resource conservation, awareness
programme about the conservation of resources, etc. They encourage the
local people for the involvement in conservation programmes.

e) Nepal Nature Conservation Fund
,W ZDV HVWDEOLVKHG LQ % 6 WR ZRUN LQ WKH ÀHOG RI QDWXUH FRQVHUYDWLRQ
It conducts various programmes like environmental education, sustainable
development programme, resource conservation, etc in various parts of our
country. It makes people aware about the environment conservation.

f) National Parks and Wildlife Reserves
National parks and wildlife reserves are government bodies which are
established to conserve plants and wildlife. There are eleven national
parks and three wildlife reserves in our country. They conserve plants,
animals, natural surroundings, etc.

g) International agencies
9DULRXV LQWHUQDWLRQDO DJHQFLHV DQG RUJDQL]DWLRQV DUH ZRUNLQJ LQ WKH ÀHOG
RI HQYLURQPHQW FRQVHUYDWLRQ 7KHVH RUJDQL]DWLRQV KDYH VLJQLÀFDQW UROH LQ
WKH IRUPXODWLRQ RI SROLFLHV DQG SURJUDPPHV LQ WKH ÀHOG RI FRQVHUYDWLRQ
of environment. United Nations Environment Programme (UNEP)

Times' Crucial Science and Environment 279 Book 7

,QWHUQDWLRQDO 8QLRQ IRU &RQVHUYDWLRQ RI 1DWXUH DQG 1DWXUDO 5HVRXUFHV
(IUCN), World Wildlife Fund for Nature (WWF), International Centre
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RUJDQL]DWLRQV ZRUNLQJ LQ WKH ÀHOG RI QDWXUH FRQVHUYDWLRQ

WŽůůƵƚĂŶƚ ͗ Ă ƐƵďƐƚĂŶĐĞ ƚŚĂƚ ĐĂƵƐĞƐ ƉŽůůƵƟŽŶ

'ĂƌďĂŐĞ ͗ ǁĂƐƚĞ ĨƌŽŵ ŚŽƵƐĞ

WůĂŶƚĂƟŽŶ ͗ Ă ƉůĂĐĞ ƚŚĂƚ ŝƐ ƉůĂŶƚĞĚ Žƌ ĐƵůƟǀĂƚĞĚ

džĐƌĞƚĂ ͗ ǁĂƐƚĞ ŵĂƩĞƌ ĚŝƐĐŚĂƌŐĞĚ ĨƌŽŵ Ă ůŝǀŝŶŐ ďŽĚLJ

^ĞǁĂŐĞ ͗ ǁĂƐƚĞ ŵĂƩĞƌ ƐƵĐŚ ĂƐ ĨĂĞĐĞƐ Žƌ ĚŝƌƚLJ ǁĂƚĞƌ ĨƌŽŵ ŚŽŵĞƐ Žƌ ĨĂĐƚŽƌŝĞƐ

ŝŽĚĞŐƌĂĚĂďůĞ ͗ ƐƵďƐƚĂŶĐĞ ĐĂƉĂďůĞ ŽĨ ďĞŝŶŐ ĚĞĐŽŵƉŽƐĞĚ

,ĂƉŚĂnjĂƌĚ ͗ ĚĂŶŐĞƌ Žƌ ƌŝƐŬ

hƌďĂŶŝnjĂƟŽŶ ͗ ŵĂŬŝŶŐ ĐŝƚLJ ĂƌĞĂ

>ĂƵŶĐŚ ͗ ƐƚĂƌƚ

0DLQ 3RLQWV WR 5HPHPEHU

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QDWXUDO UHVRXUFHV KDSKD]DUGO\ DQG H[FHVVLYHO\ ZKLFK FDXVHV
degradation in the quality and quantity of the various components
of environment.

2. Deforestation, water pollution, land pollution, air pollution,
overuse of minerals, destruction of wildlife, etc are some causes for
environmental degradation.

3. Urbanization and industrialization are also the causes for
environmental degradation.

'HVWUXFWLRQ RI IRUHVW KDSKD]DUGO\ IRU IXOÀOOLQJ QHHGV DQG ZDQWV RI
human being is called deforestation.

0L[LQJ XQQHFHVVDU\ WKLQJV VXFK DV ZDVWHV FKHPLFDOV VHZDJH HWF
to the water resources is called water pollution.

0L[LQJ ZDVWHV FKHPLFDOV JDUEDJHV HWF WR WKH ODQG LV FDOOHG ODQG
pollution.

0L[LQJ GXVW VPRNH YDULRXV W\SHV RI JDVHV IURP WKH LQGXVWULHV RU
factories to the air is called air pollution.

8. Development of the urban areas and increment of total population
residing in urban areas is called urbanization.

9. Industrialization is the process of establishing various types of
industries and development of industrial areas.

Times' Crucial Science and Environment 280 Book 7

1DWXUDO GLVDVWHUV DUH WKH QDWXUDO DFWLYLWLHV ZKLFK FDXVH WKH GDPDJH
of natural resources, man-made constructions and lives of animals.

11.Earthquake is the shaking or vibrating the surface of the earth.
12.Volcano is a vent on the earth’s surface from where hot molten

masses, hot gases, etc come out.
13.Environmental cleanliness can be carried out by the reduction,

reuse and recycle of the wastes.
14.Conservation of forest, conservation of soil, conservation of water

resources, control of pollutants, etc are some local practices for
environment conservation.
0LQLVWU\ RI IRUHVW DQG ODQG 0LQLVWU\ RI HQYLURQPHQW DQG VFLHQFH
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environment conservation.

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1. Choose the best alternative in each case.

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i. Deforestation ii. Over-population

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i. It causes the loss of shelter of wild animals.

ii. It can result in low rainfall and drying of water sources.

iii. It results in glacial lake outburst.

iv. Deforestation is carried out mainly for settlement, cultivation
and timber.

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i. Typhoid ii. Filariasis

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i. Plastic ii. Kitchen wastes

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Times' Crucial Science and Environment 281 Book 7

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L LL LLL LY

2. Fill in the blanks.

a. Iron, copper, coal, petroleum, etc are ……………….

b. Tree plantation is the best way of ………….

F ([FHVVLYH XVH RI SHVWLFLGHV PL[LQJ RI VHZDJH WR WKH ODQG
dumping of kitchen wastes near the houses or roads, etc cause
…………………

d. Diarrhoea, dysentry, typhoid, etc are caused by ……………….

e. Various facilities such as transportation, communication,
quality education, market, etc are available in ………………..

f. Shaking or vibrating of the earth’s surface is called ………….

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K ::) ,&,02' ,8&1 81(3 HWF DUH VRPH «««« DJHQFLHV
ZRUNLQJ LQ WKH ÀHOG RI ««««««

3. Match the following:

::) )RUHVW ÀUH
$FLG UDLQ
9ROFDQR
Nepal Nature Conservation Fund
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Compost manure
Well %URQFKLWLV
Underground water
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Cigarette butt

0DJPD

Bio-degradable waste

4. Answer these questions in short.
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environmental degradation.
E :KDW LV GHIRUHVWDWLRQ" 0HQWLRQ WKH FDXVHV DQG HIIHFWV RI
deforestation.

Times' Crucial Science and Environment 282 Book 7

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pollution.

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land pollution.

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SROOXWHG DLU"

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J :KDW LV XUEDQL]DWLRQ" :K\ GR SHRSOH PLJUDWH IURP UXUDO DUHDV

WR WKH XUEDQ DUHDV"
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them in brief.
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WKH HQYLURQPHQW"
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M :KDW LV HDUWKTXDNH" :KDW DUH WKH SUHYHQWLYH PHDVXUHV RI

HIIHFWV RI HDUWKTXDNH"
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O 0HQWLRQ QDPHV RI VRPH LQWHUQDWLRQDO DJHQFLHV ZRUNLQJ LQ WKH

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5. Answer these questions:
D ([SODLQ ORFDO SUDFWLFHV IRU HQYLURQPHQWDO FOHDQOLQHVV
E ([SODLQ VRPH JRYHUQPHQW RUJDQL]DWLRQV ZRUNLQJ LQ WKH ÀHOG RI
environment conservation.
F ([SODLQ KRZ XUEDQL]DWLRQ DIIHFWV WKH HQYLURQPHQW
G ([SODLQ WKH FDXVHV DQG HIIHcts of air pollution.

3URMHFW :RUN

3UHSDUH D OHDÁHW IRU PDNLQJ WKH SHRSOH DZDUH DERXW FRQVHUYDWLRQ RI
forest.

Times' Crucial Science and Environment 283 Book 7

Chapter ( QYLURQPHQW

26 D Q G 6 X V W D L Q D E O H

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OBJECTIVES

At the end of the lesson, the students will be able to :
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 ĞdžƉůĂŝŶ ƚŚĞ ŶĞĐĞƐƐŝƚLJ ĂŶĚ ŝŵƉŽƌƚĂŶĐĞ ŽĨ ĞĐŽͲĨƌŝĞŶĚůLJ ĚĞǀĞůŽƉŵĞŶƚ͘
 ĞdžƉůĂŝŶ ƚŚĞ ĞīŽƌƚƐ ĨŽƌ ƐƵƐƚĂŝŶĂďůĞ ĚĞǀĞůŽƉŵĞŶƚ ŝŶ ƚŚĞ ĐŽŶƚĞdžƚ ŽĨ

EĞƉĂů͘

MIND OPENERS
 tŚĂƚ ŝƐ ĚĞǀĞůŽƉŵĞŶƚ͍
 tŚĂƚ ŝƐ ŝƚƐ ĞīĞĐƚ ŝŶ ƚŚĞ ĞŶǀŝƌŽŶŵĞŶƚ͍
 ,Žǁ ĐĂŶ ĚĞǀĞůŽƉŵĞŶƚ ďĞĐŽŵĞ ůŽŶŐ ůĂƐƟŶŐ͍ ŝƐĐƵƐƐ͘

6XVWDLQDEOH 'HYHORSPHQW

Sustainable development refers to the development activities that are
friendly to the environment and persist for a long time. It is based on the
principle that the needs of future generation should not be hampered while
meeting the needs of present generation. Such development ensures the
preservation of natural habitat of animals, conservation of non-renewable
resources and the increased use of renewable or perpetual resources. By
the sustainable development activities, the natural environment on the
earth is not harmed beyond repair.

The United Nations initiated some efforts for the conservation of
environment while carrying out development activities. The General
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on the issues of environment, development and world support. The
commission was formed under the chairmanship of Norwegian Prime
Minister Gro Harlem Brundtland and was called Brundtland Commission.
The commission published a report entitled “Our Common Future” in 1987
$' ZKLFK LQFOXGHG WKH FRQFHSW RI sustainable development. $FFRUGLQJ WR
the Brundtland Commission, sustainable development is a developmental
process which is long lasting and does not have negative effects on the
environmental components.

Times' Crucial Science and Environment 284 Book 7

7KH GHÀQLWLRQ RI VXVWDLQDEOH GHYHORSPHQW PHDQV WKDW WKH SUHVHQW
QDWXUDO UHVRXUFHV VKRXOG EH XVHG LQ VXFK D ZD\ WKDW LW IXOÀOOV WKH SUHVHQW
requirement and remains safe for the future generation also. In general
understanding it can be stated as: the natural resources should be utilized
along with their conservation. )RU H[DPSOH WKH RYHUXVH RI QRQ UHQHZDEOH
resources causes energy crisis in future. But perpetual resources are never
ÀQLVKHG 6R SURFHVVHV PDFKLQHV RU PHFKDQLVPV PXVW EH GHYHORSHG IRU
the utilization of perpetual resources so that the overuse of non-renewable
resources is minimized. This saves the non-renewable resources for the
future generations.
The sustainable development helps to maintain a balance between
population, environment and development.

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Sustainable development is environment friendly development. It promotes
WKH H[LVWHQFH RI QDWXUDO HQYLURQPHQW DQG ZLOGOLIH 6R WKH VXVWDLQDEOH
development is essential for environmental conservation.
7KH LPSRUWDQFH RI VXVWDLQDEOH GHYHORSPHQW FDQ EH H[SODLQHG LQ WKH
following points:

1. Proper use of resources
Sustainable development enhances the proper utilization of natural
resources. The natural resources should be utilized according to their
QDWXUH 7KH SHUSHWXDO UHVRXUFHV DUH QHYHU ÀQLVKHG 6R WKH\ FDQ EH XWLOL]HG
as much as possible. But the amount of non-renewable resources is limited.
Hence, their use should be minimized so that they will remain for future.

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Times' Crucial Science and Environment 285 Book 7

2. Realization of responsibility
Sustainable development changes the knowledge, skill and attitude of
people. Hence, people realize the importance of conserving forest, soil, air,
water resources and the fossil fuels (i.e, petrol, kerosene, diesel, coal, etc).
They realize that the resources are their common properties. This supports
the conservation of natural resources.

3. Emphasis on public participation
If the people of local area participate in the developmental activities, it
increases their ownership and responsibility for the protection of developed
infrastructures. So, the development lasts for a long time and people get
PD[LPXP EHQHÀWV IURP LW

4. Long term vision
Sustainable development aims to advance economic and social development
without environmental degradation. It makes people think that the present
works will sustain in the future and the resources will be preserved for
future generation.

5. Development of basic areas
Health, education, agriculture, tourism and social improvement are
regarded as basic areas. Sustainable development emphasizes the
development of basic areas without harming the environment.

6. Determination of limit of development
$OWKRXJK WKH OLPLWHG UHVRXUFHV DUH HQRXJK WR PHHW WKH KXPDQ QHHGV
people desire to conduct the development works beyond the limit. The
development beyond limit causes the adverse effects on the environment.
So, the sustainable development helps people to develop a feeling of proper
development taking care of the environment.

(൵RUWV IRU 6XVWDLQDEOH 'HYHORSPHQW LQ 1HSDO

The objectives of sustainable development are not being met properly in
our country due to the lack of public awareness and inadequate education.
But different government and non-government organizations are working
for sustainable development in Nepal. Some local and national level efforts
for sustainable development in Nepal are discussed below:

1. Conservation of forest and afforestation
Forest is not only a natural resource but also the supporter or source of
VHYHUDO RWKHU QDWXUDO UHVRXUFHV ,W SURYLGHV IUHVK R[\JHQ WR WKH DWPRVSKHUH
KHOSV LQ UDLQIDOO SURYLGHV ÀUHZRRG WLPEHU IRGGHU PHGLFLQDO SODQWV HWF
and is the home of millions of wildlife.

Times' Crucial Science and Environment 286 Book 7

Protection of forest conserves forest as well as several other natural
resources. For the sustainable development, forest is conserved by local
consumer groups and its products are utilized by them without harming
the environmental balance. The government is also conserving the forest
and wildlife by establishing national parks, wildlife reserves and wildlife
conservation area.

$IIRUHVWDWLRQ SURJUDPPHV DUH FRQGXFWHG RQ EDUH ODQGV E\ VHYHUDO
organizations. This helps to conserve forest for the future generation.
2. Conservation of water resource
Water resource is conserved mainly by conserving the forest. Besides this,
ULYHU HPEDQNPHQWV DQG VSXUV DUH PDGH WR FRQWURO ÁRRG LQ ULYHUV )RUHVW
conservation should be done for water conservation. Different irrigation
systems are set up for using water for a long time. Hydro-electricity is
generated from the rivers which is becoming a popular source of energy in
Nepal.

3. Conservation of land
The productive quality of the land is being conserved by encouraging the
use of organic manure rather than chemical fertilizers. The soil erosion is
FRQWUROOHG E\ ORFDO DQG QDWLRQDO ERGLHV WKURXJK DIIRUHVWDWLRQ RQ EDUH ÀHOGV
and naked hills. Terrace farming is encouraged on the sloppy areas.

Times' Crucial Science and Environment 287 Book 7

4. Proper use of natural resources
0RUH HPSKDVLV LV JLYHQ WR WKH XVH RI DOWHUQDWLYH VRXUFHV RI HQHUJ\ VXFK
as solar energy, wind energy, biomass, biogas energy and hydroelectricity
rather than the use of fossil fuels. Thus, the use of fossil fuels can be
minimized.

5. Sewage and solid waste management
0L[LQJ RI VHZDJH ZLWK ULYHUV DQG ÀOOLQJ WKH GXPSLQJ VLWHV ZLWK VROLG ZDVWHV
is not the sustainable solution to the sewage and waste management.
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DQG UHF\FOH SULQFLSOH IRU WKH PDQDJHPHQW RI VROLG ZDVWHV $FFRUGLQJ WR
this principle, the amount of solid waste production is reduced as much as
possible. Similarly, the usable substances are recycled after their use and
then reused. Thus, very less amount of waste is produced and it is easier
to manage it.

6. Proper management of industries
The government of Nepal is adopting a policy of establishing industries
away from the settlement areas. This reduces the disturbance and pollution
from the industries to the people.
7. Public awareness programmes
The principles and the importance of sustainable development are taught
in the school. This helps students to generate and use the techniques of
sustainable development. Sometimes, awareness programmes are also
conducted through drama, pamphlet, documentary show etc.

Times' Crucial Science and Environment 288 Book 7

^ƵƐƚĂŝŶ ͗ ƐƵƉƉŽƌƚ
DĞĐŚĂŶŝƐŵ ͗ ƐLJƐƚĞŵ ŽĨ ƉĂƌƚƐ ǁŽƌŬŝŶŐ ƚŽŐĞƚŚĞƌ
,ĂŵƉĞƌĞĚ ͗ ĚŝƐƚƵƌďĞĚ
,ĂďŝƚĂƚ ͗ ŶĂƚƵƌĂů ŚŽŵĞ
ŝŽŐĂƐ ͗ ŐĂƐĞŽƵƐ ĨƵĞů ƉƌŽĚƵĐĞĚ ĨƌŽŵ ĚĞĐĂLJŝŶŐ ŽĨ ŽƌŐĂŶŝĐ ŵĂƚĞƌŝĂůƐ
WĂŵƉŚůĞƚ ͗ ƐŵĂůů ŬůĞƚ Žƌ ůĞĂŇĞƚ ĐŽŶƚĂŝŶŝŶŐ ŝŶĨŽƌŵĂƟŽŶ

0DLQ 3RLQWV WR 5HPHPEHU

1. Sustainable development refers to the development activities that
are friendly to the environment and persist for a long time.

$FFRUGLQJ WR %UXQGWODQG FRPPLVVLRQ VXVWDLQDEOH
development is a developmental process which is long lasting and
does not have negative effects on the environmental components.

3. The importance of sustainable development can be summarized in
the following points:
a. Proper use of resources

E 5HDOL]DWLRQ RI UHVSRQVLELOLW\
c. Emphasis on public participation
d. Long term vision
e. Development of basic areas
f. Determination of limit of development

4. In Nepal, following efforts are done for the sustainable development:
a. Conservation of forest and afforestation
b. Conservation of water resource
c. Conservation of land
d. Proper use of natural resources
e. Sewage and solid waste management
f. Proper management of industries
g. Public awareness programmes

([HUFLVH

1. Answer these questions in very short.
D :KDW GR \RX PHDQ E\ VXVWDLQDEOH GHYHORSPHQW "

Times' Crucial Science and Environment 289 Book 7

E :KDW LV %UXQGWODQG FRPPLVVLRQ "
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2. Write down short notes on:
a. Forest conservation
b. Water conservation
c. Proper use of energy sources
d. Public participation

3. Answer these questions:
D 'HÀQH VXVWDLQDEOH GHYHORSPHQW
E ([SODLQ WKH LPSRUWDQFH RI VXVWDLQDEOH GHYHORSPHQW
c. How do awareness programmes support in sustainable
GHYHORSPHQW "
G ([SODLQ WKH HIIRUWV WKDW DUH EHLQJ PDGH IRU VXVWDLQDEOH
development in Nepal.

4. Study the given diagram and answer the questions that follow:

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E +RZ GRHV LW DIIHFW WKH HQYLURQPHQW "
F :KDW LV WKH VXVWDLQDEOH VROXWLRQ WR WKH DERYH SUREOHP "

Times' Crucial Science and Environment 290 Book 7

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S.N. Topics No. of Sub Marks Abilities Remarks Total
questions questions marks
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Subject: Science and Environment — 7

Terminal exam Physics Chemistry Biology Geo/Astronomy Environment

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practicable.

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structure of a dry cell with the help of a diagram. > @

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symbol of iron and copper. > @

b. Write the molecular formula of the following compounds: > ð @

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structure of common salt and copper sulphate. > @

b. Write down difference between dilute and concentrated solution.

State any two uses of solution. > @

7. a. Write down any four properties of metals. > @

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8. a. Write the importance of nitrogen and phosphorus in plants.

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animals and classify them with one main character. > @

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angiosperms and gymnosperms. > @

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function of cell wall. > @

Times' Crucial Science and Environment 294 Book 7

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juice and pancreatic juice. > @

b. Describe the process of breathing in insects > @

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Igneous rock, metamorphic rock > @

b. Study the table and answer the questions:

Planet Distance from the sun Time of rotation Time of revolution

$ ð 7 km 243 days 225 days

B ð 7 km 24 days 365 days

C ð 7 km KRXUV 12 years

D ð 7 km KUV PLQ 29.5 years

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deforestation. > @

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sustainable development. > @

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Times' Crucial Science and Environment 295 Book 7

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A project work will have to be completed and submitted to the concerned
teacher by each student before each term. The full marks for the project
work will be 10.

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Teacher may select any two questions from the following list for conducting
the practical examination during each terminal examination. The full
marks of the exam will be 15.
1. Show that pressure increases with force.
2. Show that an iron rod is a good conductor of heat.
3. Show that water is a bad conductor of heat.
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5. Prove that sound travels faster in solid than in liquid.
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7. Show that the voltage and current increase in series combination of cells.
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9. Prepare dilute solution of sugar in water.
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the help of conductivity test.
11. Take a complete plant (a plant with complete root and shoot system)

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and main characteristics.
13. Demonstrate the process of breathing in human body.
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15. Observe the structure of amoeba under a microscope and study its

parts.

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Times' Crucial Science and Environment 296 Book 7