St. John’s E.M High School(Affiliated to the Central Board of Secondary Education, New Delhi)

Class: VIII ____________________________________________________________________________________________

Stay Home Stay Fit

Now you know regular

children and young people. Copy the given poses and hold for

20 seconds. Relax.

The exercises given in this Worksheet are

supposed to be done in a new notebook…..

St. John’s E.M High School(Affiliated to the Central Board of Secondary Education, New Delhi)

Vijayawada

Worksheet – 3, 2020-21 ____________________________________________________________________________________________

egular exercise has lots of health

children and young people. Copy the given poses and hold for

The exercises given in this Worksheet are

supposed to be done in a new notebook…..

St. John’s E.M High School (Affiliated to the Central Board of Secondary Education, New Delhi)

Date: 01-05-2020

____________________________________________________________________________________________

health benefits for

children and young people. Copy the given poses and hold for

The exercises given in this Worksheet are

supposed to be done in a new notebook…..

Subordinating Conjunctions :

A subordinating conjuction is a word that connects a main clause to a subordinate

clause. A main clause is an independent clause that can stand alone by itself as a sentence.

In other words, a main clause does not need any additional information to operate as a

sentence.

1. We were happy ………………. we received the first prize.

a) because b) if c) before

2. The people were listening eagerly ……………….. the leader was speaking.

a) since b) while c) after

3. This is the place ………………. we were attacked.

a) when b) where c) while

4. ………………… he worked hard, he failed. Please select 2 correct answers

a) Although b) Though c) even if

5. ...................... she is beautiful, she is not intelligent.

a) Though b) As c) Because

6. You wait here ……………. I come.

a) unless b) until c) before

7. She will not come …………….. we compel her.

a) if b) unless c) whether

8. There was a silence ……………….. the guests had gone.

a) Until b) after c) whether

THOROUGHLY READ THE ABOVE CONCEPT, UNDERSTAND IT AND ANSWER THE

BELOW PRACTICE QUESTIONS:

9. She began to cry ………………… she had lost her golden chain.

a) whether b) because c) if

10. ..................... you work hard, you will get the first prize.

a) If b)Unless c) whether

11. She became angry …………………. I had said anything.

a) before b) as c) when

………………………………………………………………………………………………

Ch -3 SYNTHETIC FIBRES & Plastics

PLASTICS

Plastics are synthetic materials that can be moulded into different shapes. Like

synthetic fibres plastics are also polymers. Monomers in all plastics do not have same

type of arrangements. In some it is linear and in others it is cross-linked arrangement.

Based on their characteristics and reaction to heat, plastics are of two types.

a) Thermoplastics b) Thermosetting plastics.

Thermoplastics can be bent easily and they deform on heating. They can be

remoulded and reshaped. These plastics are recyclable. Ex: Polythene, PVC( Poly

Vinyl Chloride), Polystyrene etc. These are used in manufacturing toys combs and

various types of containers.

Thermosetting plastics cannot be bent and they break when forced to bend. These

are the plastics which when moulded once cannot be softened by heating. Ex:

Bakelite, Melamine, Teflon etc...

Bakelite is used for making electrical switches and handles of sauce pans.

Made of

Bakelite

Teflon coating is given to impart non-sticky nature to cooking pans.

Melamine can resist fire and tolerate heat better than other plastics. It is used in

making floor tiles, kitchen tops, utensils, and fire resistant fabrics. Melamine coating

is given on firemen dress to make them flame resistant.

Plastics are materials of choice

Plastics are light is weight, strong, durable, they can be shaped into any form .

Plastics are less expensive than metals.

Plastics are non-reactive. This property makes them best suitable in making syringes,

gloves, packaging of tablets, and a number of medical instruments.

Plastics do not react with water and air. They are not corroded easily.

Plastics are poor conductors of electricity.

Plastics and environment

Materials that decompose easily by natural processes are called biodegradable.

Materials that cannot be decomposed easily by natural processes are called non-

biodegradable. Non-biodegradable materials take more than 100 years to decompose.

This leads to environmental hazards if not disposed properly. Plastics are non-

biodegradable.

Burning of plastic releases poisonous fumes into atmosphere and cause air pollution.

Plastic disposed in water bodies is choking the respiratory organs of aquatic animals

and posing threat to their lives.

In the process of eating food from the garbage dump, animals like cows, swallow

plastic. The plastic chokes the respiratory system of cows and forms a lining in their

stomach and can cause their death.

Carelessly thrown polybags find their way to sewage system and block the drains.

Single use plastic should be avoided.

Biodegradable and non-biodegradable wastes must be disposed separately in green

and blue bins respectively.

We should follow 5R principle

Recycle. During recycling colouring agents may be added to plastic, so recycled

plastic is not suitable for food storage.

Choose the correct answers

1. A plastic that can be remoulded on heating.

a) PVC b) Bakelite

2. The plastic used as a coating on non

a) polythene b) polystyrene

3. How should you dispose the plastic bags used by you

a) throw it on road

c) throw it in green bin

Answer the following:

4. Electric plugs/switches/plug boards are made of thermosetting plastics. Give the

reason.

5. What is 5R principle?

6. What are biodegradable and non

………………………………………

THOROUGHLY READ THE ABOVE CONCEPT, UNDERSTAND IT AND ANSWER THE

BELOW PRACTICE QUESTIONS:

5R principle. R-Refuse, R-Reduce, R- Reuse, R

Recycle. During recycling colouring agents may be added to plastic, so recycled

plastic is not suitable for food storage.

answers

A plastic that can be remoulded on heating.

b) Bakelite c) Melamine d) all of these.

The plastic used as a coating on non-stick pans is

b) polystyrene c) teflon d) None of these.

d you dispose the plastic bags used by you

b) throw it in water bodies

c) throw it in green bin d) throw it in blue bin

Electric plugs/switches/plug boards are made of thermosetting plastics. Give the

What are biodegradable and non-biodegradable materials?

………………………………………….…………………………………………….

THOROUGHLY READ THE ABOVE CONCEPT, UNDERSTAND IT AND ANSWER THE

BELOW PRACTICE QUESTIONS:

Reuse, R- Recover, R-

Recycle. During recycling colouring agents may be added to plastic, so recycled

c) Melamine d) all of these.

d) None of these.

b) throw it in water bodies

Electric plugs/switches/plug boards are made of thermosetting plastics. Give the

…………………………………………….

THOROUGHLY READ THE ABOVE CONCEPT, UNDERSTAND IT AND ANSWER THE

TYPES OF RESOURCES:

� Resources are categorised into natural, human made and human.

1. Natural resourcesare those resources that are drawn from nature and are used without

much modification-air, water, soils, minerals

� Natural resources are classified into different groups depending upon their level of

development and use, origin, renewability and distribution

� Natural resources also called as 'gifts of nature'.

Resources are categorised into natural, human made and human.

are those resources that are drawn from nature and are used without

air, water, soils, minerals are the natural resources.

Natural resources are classified into different groups depending upon their level of

development and use, origin, renewability and distribution

Natural resources also called as 'gifts of nature'.

Resources are categorised into natural, human made and human.

are those resources that are drawn from nature and are used without

are the natural resources.

Natural resources are classified into different groups depending upon their level of

(i) On the basis of level of their development and use

classified into –

ACTUAL RESOURCES

Those resources whose quantity is

known.

These resources are being used in the

present.

For e.g. Coal of Germany, Petroleum in

the West Asia

(ii) On the basis of origin, the natural resources can be

BIOTIC RESOURCES

It includes all the living things.

For example- Plants & animals

(iii) On the basis of renewability or stock

RENEWABLE RESOURCES

Those which can get renewed or

replenished quickly are called

as Renewable resources. They

are also called as Inexhaustible

resources.

For e.g. solar and wind energy.

level of their development and use, natural resources can be

ACTUAL RESOURCES POTENTIAL RESOURCES

Those resources whose quantity is Those resources whose entire

quantity may not be

These resources are being used in the These are not being used at present

and could be used in the future.

For e.g. Coal of Germany, Petroleum in For e.g. The Uranium in Ladakh

, the natural resources can be

BIOTIC RESOURCES ABIOTIC RESOURCE

It includes all the living things. It includes all the non

Plants & animals For example- Soil, rocks, minerals

(iii) On the basis of renewability or stock, natural resources can be categorized into

RESOURCES NON-RENEWABLE RESOURCES

Those which can get renewed or

replenished quickly are called

as Renewable resources. They

Inexhaustible

Those which have a limited stock. Once

the stocks are exhausted it may take

thousands of years to be renewed or

replenished are called as Non

resources. They are also called as

Exhaustible resources

For e.g. solar and wind energy. For e.g. such as coal, petroleum and

natural gas.

, natural resources can be

POTENTIAL RESOURCES

Those resources whose entire

quantity may not be known

These are not being used at present

and could be used in the future.

For e.g. The Uranium in Ladakh

ABIOTIC RESOURCES

It includes all the non-living things.

Soil, rocks, minerals

, natural resources can be categorized into

RENEWABLE RESOURCES

Those which have a limited stock. Once

the stocks are exhausted it may take

of years to be renewed or

replenished are called as Non- renewable

resources. They are also called as

For e.g. such as coal, petroleum and

(iv) On the basis of distribution

UBIQUITOUS RESOURCES

Ubiquitousresourcesarefoundeverywhereo

n the earth. Land, water, air areubiquitous

resources.

� The distribution of natural resources depends upon, number of physical factors like

terrain, climate and altitude(height).

� The distribution of resources is unequal across the earth.

2.Human Made Resources:

Human resource refers to the number(quantity) and

people.

(i) The resources which are created from the natural resources by the human resources by

the human beings to produce useful products are known as Human made resources. Like

roads, machinery, vehicles, etc.

(ii) Technology is also a human made resources.

(iv) On the basis of distribution, natural resources can be classified into

UBIQUITOUS RESOURCES LOCALIZED RESOURCES

Ubiquitousresourcesarefoundeverywhereo

n the earth. Land, water, air areubiquitous

Localized resources are

found only in certain places,

like copper and iron ore.

The distribution of natural resources depends upon, number of physical factors like

terrain, climate and altitude(height).

The distribution of resources is unequal across the earth.

Human resource refers to the number(quantity) and abilities (mental and physical) of the

(i) The resources which are created from the natural resources by the human resources by

the human beings to produce useful products are known as Human made resources. Like

roads, machinery, vehicles, etc.

) Technology is also a human made resources.

resources can be classified into-

LOCALIZED RESOURCES

Localized resources are

found only in certain places,

like copper and iron ore.

The distribution of natural resources depends upon, number of physical factors like

abilities (mental and physical) of the

(i) The resources which are created from the natural resources by the human resources by

the human beings to produce useful products are known as Human made resources. Like

3. Human Resources:

(i) Human resources refer to the number and abilities of the people. People can make the

best use of nature to create more resources when they have the knowledge, skill and the

technology.

(ii) People are human resources.

(iii) Improving the quality of people's skills so that they are able to create more resources

is known as Human resource development.

Fill in the Blanks

(i) The types of resources on basis of stock are …………………. and

…………………………. resources.

(ii) Although renewable resources can be replenished, we should be ……………

regarding their use.

(iii) Coal and petroleum are examples of ………….. resources.

(iv) Air is a ubiquitous resource since it is found ………………..

(v) Physical factors affecting the presence of a localised resource are …………….. ,

……………… and ……………

THOROUGHLY READ THE ABOVE CONCEPT, UNDERSTAND IT AND ANSWER THE

BELOW PRACTICE QUESTIONS:

Multiple choice Questions

(i) Which one of the following is a human made resource?

(a) Medicines to treat cancer (b) Spring water

(c) Tropical forest (d) None of the above

(ii) Which of the following is a non-renewable resource?

(a) solar energy (b) water (c) soil (d) natural gas

State True or False

(i) With respect to electricity, water was a potential resource until few years back.

(ii) Allnaturalsources of energy are renewable.

(iii) A farmer is a human resource.

Question and Answers

(i) Why are humanbeings resources?

(ii) Explain how resources are classified broadly.

(iii) Describe how natural resources are classified.

(iv) Differentiate between natural resources and human made resources

(v) Why are resources distributed unequally over the earth?

(vi) How potential resource can be actual resource?

……………………………………………………………………………………………..

PROPERTIES OF RATIONAL NUMBERS:

1) CLOSURE PROPERTY

2) COMMUTATIVE PROPERTY

3) ASSOCIATIVE PROPERTY

4) IDENTITY PROPERTY

5) INVERSE PROPERTY

6) DISTRIBUTIVEPROPERTY

……………………………………………………………………………………………..

THOROUGHLY READ THE ABOVE CONCEPT, UNDERSTAND IT AND ANSWER THE

BELOW PRACTICE QUESTIONS:

English Key :

Maths Key :

1.a)True b)True c)False d)False e)True f)False

2. 1 3. No 4. 1 5. Prime, composite

6. A)½ B) ¼ C) 0 , yes all these are rational numbers

Social Key :

CHECK YOUR UNDERSTANDING –01 KEY

Fill in the Blanks

(i) value (ii) Time and Technology

(iii) Economic Value or Aesthetic Value

Multiple choice Questions

(i) None of these (ii) Mountains

State True or False

(i) False (ii) True

Question and Answers

(i) A substance needs to have some utility to be called a resource.

(ii) If a substance can be used in any way, it is said to have a utility.

(iii) Utility or usability is what makes an object or substance a resource.

(iv) Patent: It means the exclusive right over any idea or invention.

Technology: Technology is the application of latest knowledge and skill in doing or

making things.

(v) Time and technology are two important factors that can change substances into

resources.

� Each discovery or invention leads to many others.

� Ex: The discovery of fire led to the practice of cooking and other processes while

the invention of the wheel ultimately resulted in development of newer modes of

transport.

*****

The following are the links of NCERT text books .

Click on them to view the lessons

Class VIII Science..

Synthetic Fibres : http://ncert.nic.in/textbook/textbook.htm?hesc1=3-18

Class VIII Social ... Geography Ch. 1 Resources

http://ncert.nic.in/textbook/textbook.htm?hess4=1-6

CLASS VIII MATHS :

Rational numbers : http://ncert.nic.in/textbook/textbook.htm?hemh1=1-16