2 Oasis School Science and Technology -4 Approved by Curriculum Development Centre
Approved by Government of Nepal, Ministry of Education, Science and
Technology, Curriculum Development Centre (CDC), Sanothimi Bhaktapur
Editor
7Dr. Chinta Mani Panthee
M.Sc., Ph.D.
7
Author
Dr. Subodh Kumar Upadhyaya
M.Sc., Ph.D.
Anamnagar, Kathmandu, Nepal
Phone: 0977-01-4313205
Approved by Curriculum Development Centre Oasis School Science and Technology -4 3
Publisher and Distributor: Approved by Curriculum Development Centre
Oasis Publication Pvt. Ltd.
Tel: 00977-1-4313205
Author:
Dr. Subodh Kumar Upadhyaya
Language Editors:
Romharsh Panthi
Jagadish Pokhrel
Edition:
First : 2079
Copyright
Author and Editor
Computer layout:
Oasis Desktop Group
Printed in Nepal
4 Oasis School Science and Technology -4
Preface
Oasis School Science and Technology for Grade 4 is an attempt to make learning
process a joyful experience. This textbook has been written in strict conformity with
the latest syllabus prescribed by the Curriculum Development Centre, Sano Thimi,
Bhaktapur, Nepal. This book has been designed to help students develop their
conceptual thinking and scientific skills. I think this book is an excellent introduction
to experimentation and practical application of Science. I hope it will greatly facilitate
teaching learning process in an easy and enjoyable manner.
The beauty of this textbook lies in having high resolution pictures, attractive layout,
and clear illustrations with lucid language. It emphasizes concept building rather
than merely focusing on providing and collecting information without critical
thinking. I expect this book will assist students to make them eager and quizzical
learners that reinforces their conceptual learning in the classroom. Besides the
learning process of the students, this book will help in teaching process of the
teachers. Each unit of this book presents subject matter in an interesting,
understandable and enjoyable manner. The exercise at the end of each unit includes
a variety of questions to facilitate the integration of various concepts taught. Above
all, I sincerely believe that this book will be helpful in overall understanding of
Science in an interesting manner.
It is not a hidden fact that modern era is the era of science and technology. Science is
a part of the world we live in and an avenue to the technology. A good textbook in
science should assist the learners to realize different activities and events around us
that encourages them for further discovery and innovation interestingly. I strongly
believe that students should enjoy science and this book will be a means of enjoying
and learning science in the modern era of science and technology.
I wish to express my sincere gratitude to Mr. Surendra Karki, Managing director of
Oasis Publication Pvt. Ltd. for publishing this book. Similarly, thanks are due to Mr.
Deepak Bahadur Bista, Ashim (Indra) Rijal, Deepak Banjade, Dilip Belbase, Srijan
Pasachhe, Shree Ram Lamsal and Srijan Adhikari for their valuable help during the
preparation and content editing of the book. Likewise, thanks are due to Mr. Jagadish
Pokhrel for his praiseworthy language editing.
In my opinion, the real judges of a book are the teachers concerned and the students
for whom it is meant. Despite all my efforts, there might be textual as well as technical
errors. Therefore, constructive suggestions for rectification and improvement of the
book would be gratefully acknowledged and incorporated in further editions.
Author
Approved by Curriculum Development Centre Oasis School Science Kathmandu, N-4epal.5
and Technology
Contents
Unit : 1 Scientific Learning 7-24
Unit : 1 .1 Scientific Learning Process 8
Unit : 1.2 Measurement 15
Unit : 2 Information and Communication Technology 25-63
Unit : 2.1 Means of Communication 26
Unit : 2.2 Introduction to Computer 35
Unit : 2.3 Paint Software 44
Unit : 2.4 The Internet 57
Unit : 3 Organisms and environment 64-84
Unit : 3.1 Environment
65
Unit : 3.2 The interrelationship between organisms
and the environment 75
Unit : 4 Classification of living things 85-107
Unit : 4.1 Animals around us 86
Unit : 4.2 Plant around us 97
Unit : 5 Life process 108-129
Unit : 5.1 Animal life 110
Unit : 5.2 Plant life. 118
Unit : 6 Matter 130-162
Unit : 6.1 Water 132
Unit : 6.2 Air 146
Unit : 6.3 Rock 155
Unit : 7 Energy 163-190
Unit : 7.1 Introduction to energy 164
Unit : 7.2 Electricity 175
Unit : 7.3 Magnetic and non-magnetic substances 182
Unit : 8 Earth and Space 291-224
Unit : 8.1 The Earth
192
Unit : 8.2 Weather 201
Unit : 8.3 Natural Disaster 211
6 Oasis School Science and Technology -4 Approved by Curriculum Development Centre
UNIT
1 Scientific Learning
Introduction
We learn from our surroundings. We share what we have learnt with
others. For example, our ancestors noticed that rubbing two stones
against each other created sparks. Then, they learnt to make fire and
taught their children to do so. They saw fish swimming in water. They
might have thought they could swim, too. Similarly, flying birds
might have inspired humans to make aeroplanes. By nature, humans
observe their surroundings, collect information, make predictions
and do experiments. This overall process of learning and transferring
knowledge makes the basis of science. The continuous process of
learning that includes observation, collecting information, analysing
data, making a prediction, conducting an experiment and drawing
the conclusion is called scientificlearning. The scientific learning
process involves a set of skills for observation and experiment.
fish swimming in water lightning flying birds
Fact file
Charles Darwin discussed evolution of life in his book ‘On
the Origin of Species’.
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Unit Scientific Learning Process
1.1
Key terms and terminologies
1. Scientific learning: The continuous process of learning that includes
observation, collecting information, analysing data, making a prediction,
conducting an experiment and drawing the conclusion is called scientific
learning.
2. Scientific learning processes: The transferable skills such as observation,
measurement, comparison, analysing, conducting experiments etc. are
called scientific learning processes.
3. Experiments: Scientific experiments are those activities that are done to
verify our predictions.
4. Observation: The act of viewing the events to collect information is called
observation.
Introduction
Scientific learning process requires some sets of skills. They are
observation, collecting information, asking questions, analysing data,
making a hypothesis, experimenting and drawing conclusions.
The transferable skills such as observation, measurement, comparison,
analysing, conducting experiments etc. are called scientific learning
processes.
Observation is the first skill of a child observing a flower with a hand lens.
scientific learning process. It Approved by Curriculum Development Centre
allows us to collect information.
Analysis of the information
helps us to form a hypothesis. It
is verified by experiments and
concluded at last.
8 Oasis School Science and Technology -4
Resonable facts
Why are scientific skills important?
Scientific skills are important because they help us to
understand the question and develop the idea to find
its answer.
Activity
Collect some materials such as sugar, salt, oil, spices,
etc. from the kitchen. Put them in water. Are all of them
soluble in water? Fill in the table below.
Water-soluble Water-insoluble
Scientific learning is very important because it helps us understand
our environment. It helps us discover new things. It helps us in the
invention of new technology. For example, Thomas Alva Edison
invented the light bulb, Graham Bell invented the telephone, Marconi
invented the radio, etc.
Edison made light bulb Graham Bell invented Marconi invented radio
telephone
Fact file
James Watt invented the steam engine.
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Scientific experiment
An experiment is a scientific learning skill. It tells us whether our
understanding of something is correct or not. Scientific experiments
are the activities that verify our predictions. Generally, they are
carried out in the science laboratory. They can also be performed at
home and in school. Some experiments are indoor and others are
outdoor. Scientific experiments are fun. Some of them are pretty
dangerous as well.
We should be very careful in the
science lab. We should follow the
directions of the teacher and
handle the laboratory apparatus
carefully. We should observe the
experiments very carefully. students doing experiments in the science lab.
Keeping notes of any new
information is a good idea. The information can then be used for
making predictions.
Activity
Take 10ml water in a beaker.
Put some salt in the water
and stir it. Do you still see
the salt? Where does the salt
go? Boil the water until all of
it evaporates. Do you see the
salt in the beaker?
Fact file
There is a science laboratory in space called international
space station.
10 Oasis School Science and Technology -4 Approved by Curriculum Development Centre
Resonable facts
Why should we wear gloves in a chemistry lab?
We should wear gloves in a chemistry lab because
chemicals can burn for our skin.
Precautions in the science laboratory
i. We should not touch chemicals with our bare hands.
ii. We should handle apparatus carefully.
iii. We should store apparatus and chemicals properly.
iv. We should not eat and drink in the lab.
v. We should not play in the lab.
Summary
1. Scientific learning requires skills of observation, collecting information,
asking questions, analysing data, making a hypothesis, experimenting
and concluding.
2. The learning process which involves a set of scientific skills is
called scientific learning.
3. The skills to practise the scientific learning process can be learnt
and transferred.
4. Scientific experiments are activities done to verify the predictions.
5. Do not touch chemicals with bare hands.
Model Questions with Their Answer
1. What is observation?
The act of viewing events to collect information is called
observation.
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2. Define scientific experiments.
Scientific experiments are the activities that are carried out to
verify our predictions.
3. Why is the scientific experiment important?
The scientific experiment is important because it helps us to test
our hypothesis.
4. We should be careful in a science lab. Why?
We should be careful in a science lab because carelessness causes
accidents.
5. Describe the scientific learning process with an example.
The scientific learning process requires certain skills.
If I see a fruit in my garden, I would need to follow the scientific
learning process to know more about it.
Observation : I should observe the colour, shape, size
and smell of the fruit.
Asking question : I should ask questions about the fruit
with elders.
Collecting information : I should make a list of information
obtained by asking questions.
Forming hypothesis : I should predict if the fruit is edible or
not.
Conclusion : I should confirm if it is edible or not.
Exercise
1. Fill in the blanks with an appropriate word.
scientific learning teacher scientific light experiment
process learning bulb
a. Observation is the first skill of …….
b. Some of the …… ……….. is pretty dangerous as well.
c. Thomas Alva Edison invented ……………
12 Oasis School Science and Technology -4 Approved by Curriculum Development Centre
d. We should follow the directions of the ………..
e. The skills to practise the .………. can be learnt and transferred.
2. Write true for the correct and false for the incorrect statement.
a. We should not touch chemicals with our bare hands.
b. We should not play in the lab.
c. It is ok to eat lunch in the laboratory.
d. Scientific learning skills cannot be learnt.
e. Graham Bell invented the telephone.
3. Choose the best answer from the given alternatives.
a. Which one is a scientific learning skill?
observation experiment questioning all of them
b. Who invented the telephone?
Marconi Darwin Graham Bell None
c. What did Marconi invent?
theory of evolution steam engine radio gravity
d. Which one is not a step of the scientific learning process?
observation experiment prediction cleaning
e. What should we do in the science lab?
eat run play observe
4. Match the following.
Chemicals helps in prediction
Observation act to verify prediction
Scientific experiment Graham Bell
Telephone do not touch
Analysis act of viewing events
5. Answer the following questions in a word.
a. What is the first step of the scientific learning process?
b. What is the activity that helps to verify our predictions?
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c. Who invented the light bulb?
d. Who should we listen to in the science lab?
e. What is the term used for the learning process that involves
a particular set of skills?
6. Write any two differences between:
a. Observation and experiment
7. Give reason.
a. We should not touch chemicals with our bare hands.
b. We should listen to the teacher in the science laboratory.
c. We should learn scientific learning skills.
8. Study the given diagram and answer the following questions.
i. Observe diagram and note colour, shape and size
of the fruit.
ii. Ask your teacher or elders about the test of the
fruit.
iii. Discuss if it is edible or not.
9. Answer the following questions.
a. What is scientific learning?
b. Define the scientific learning process.
c. Make a list of scientific learning skills.
d. How do you collect information for research?
e. What is scientific experiments?
f. Where are experiments done?
g. What should we never do in the science laboratory?
h. What should we do during experiments?
10. Project work.
Describe the scientific learning process with an example.
14 Oasis School Science and Technology -4 Approved by Curriculum Development Centre
Unit Measurement
1.2
Key terms and terminologies
1. Measurement: The process of comparison of an unknown quantity with a known
and standard quantity of the same kind is called measurement.
2. Physical quantities: Those quantities that can be measured using physical devices
are called physical quantities.
3. Units: Units are the standard reference form of a physical quantity.
4. Schematic diagram: The diagram that is drawn using lines only to show the main
part of the apparatus is called a schematic diagram.
5. Mass: The total amount of matter present in a body is called mass.
6. Length: The distance between any two points is called length.
7. Volume: The total space occupied by a body is its volume.
8. Time: The duration between any two events is called time.
Introdduction
How do we buy things from the market? How do we measure time?
People use measurement to buy and sell things. To do so, shopkeepers
have standard known quantities such as meter tape, kilogram weigh,
measuring cylinder etc. We know the exact value of these substances.
They use it to compare unknown quantities such as rice, milk, rope,
pipe, etc. before selling. The process of comparison of an unknown
quantity with a known standard quantity of the same kind is called
measurement.
mass of vegetable is being measured in a tailor measuring clothes 15
digital balance
Oasis School Science and Technology -4
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Fact File
Unit of length, i.e. centimetre started from France.
Fact with reason
Why should we measure physical quantities?
We should measure physical quantities to know their
exact value.
Ruler is a standard known substance. Let’s say we have a 30 cm long
ruler. If we want to know the length of the pencil, we need to put the
ruler along with the pencil. It is called comparing. Then we can tell
how long a pencil is. If our pencil is 25 cm long, it means it is 25 times
longer than 1 cm in length.
Length of pencil is unknown. It is compared with ruler so that we
can know its length.
Activity
Take a ruler. Try to measure the length, breadth and height
of your desk.
We cannot measure everything. Happiness, sadness, anger, etc.
cannot be measured. These are called non-physical quantities.
However, mass, length, time, area, volume, etc. can be measured.
Those quantities that can be measured using different physical devices
are called physical quantities.
When the measurement is done it must be expressed to another
person. To make other people understand easily units are used. So,
Units are the standard reference form of a physical quantity.
16 Oasis School Science and Technology -4 Approved by Curriculum Development Centre
Fact File
A very short moment is called jiffy.
Fact with reason
Why is mass called a physical quantity?
The mass is called a physical quantity because it can be
measured by using physical balance.
Mass is measured by pan balance. Unit of mass is kilogram, gram,
pound, pau, dharni etc. These units are useful while buying rice,
vegetables, meat, sugar, etc.
Digital balance weighing mass pan balance
Length is measured by using measuring tape. Unit of
length is meter, centimetre, foot, haat, bitta etc. These
units are useful while buying rope, clothes, wood,
land, etc. measuring tape
The volume of liquid is measured by a measuring cylinder. Litre,
cubic meter, mana, pathi etc. are units of volume. These units are
useful while buying oil, milk, water, etc. Mana pathi is used in a rural
area while buying rice, wheat, maize, etc.
Pathi is used to measure volume of rice measuring cylinder is used to measure
Approved by Curriculum Development Centre volume of liquid
Oasis School Science and Technology -4 17
Activity
Discuss with your grandparents about tools that were used
for measurement and make a list.
The duration between any two events is called time. It is measured by
using clock. Unit of time is second, minute, pal, etc. It is useful to plan
our daily activities.
quartz clock pendulum clock atomic clock hourglass
Fig: some devices to measure time
Fact File
The atomic clock is the most accurate clock on the Earth.
Measurement is very important because:
i. Measurement helps in buying and
selling things.
ii. It helps in preparation of food and
medicine.
iii. As a result of measurement,
scientific experiments will have
fewer errors. scientist doing the experiment
iv. Using measurement size of house,
road, dress, shoes, etc. can be made easily.
Schematic diagram
Measurement is a part of the scientific learning process. It is required
while collecting information. It also helps in experiments. Scientific
18 Oasis School Science and Technology -4 Approved by Curriculum Development Centre
experiments need a lot of apparatus and tools. People use a schematic
diagram of these apparatus instead of the real diagram. Real diagram
blocks the main part of the tool. Therefore, schematic diagrams are
used because it is simple and clear. The diagram that is drawn using
lines only to show the main part of the apparatus is called a schematic
diagram.
funnel schematic diagram of funnel
tripod stand schematic diagram of tripod stand
conical flask schematic diagram of conical flask
gas jar schematic diagram of gas jar 19
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Activity
Observe test tube, funnel, beaker, tripod stand, round
bottom flask and sketch their schematic diagrams.
Fact with reason
Why should we draw a schematic diagram instead
of a 3D diagram?
We should draw a schematic diagram instead of a
3D diagram because schematic diagrams do not
block important parts of the picture.
The schematic diagram is very popular in the scientific learning
process because of the following reasons:
i. It does not block the main part of the apparatus.
ii. It is easy to draw.
iii. It is easy to understand.
Fact File
The schematic diagram should not be three dimensional.
Some of the basic things that are required for drawing schematic
diagram are:
i. Only sharp pencils should be used to draw the lines.
ii. Use rulers to draw lines.
iii. The image must be two dimensional.
iv. Colouring and shading are not allowed.
v. Use straight lines while labelling.
vi. The size of the different parts of the image must be proportional.
20 Oasis School Science and Technology -4 Approved by Curriculum Development Centre
Summary
1. The process of comparison of an unknown quantity with a known
and standard quantity of the same kind is called measurement.
2. The quantities that can be measured using physical devices are
called physical quantities.
3. Units are the standard reference form of a physical quantity.
4. Unit of mass is kilogram, gram, pound, pau, dharni, etc.
5. Unit of length is meter, centimetre, foot, haat, bitta etc.
6. Litre, cubic meter, mana, pathi etc. are the units of volume.
7. Units help to express measurement easily.
8. Measurement is a part of the scientific learning process.
9. The diagram that is drawn using lines only to show the main part
of the apparatus is called a schematic diagram.
Model Questions with Their Answer
1. What is measurement?
The process of comparison of an unknown quantity with a known
and standard quantity of the same kind is called measurement.
2. Which devices are used to measure length?
Ruler, meter rod and measuring tape are used to measure length.
3. What kinds of diagrams are called schematic diagram?
The diagrams that are drawn using lines only to show the main
parts of the apparatus are called schematic diagrams.
4. We use schematic diagrams in science books. Why?
We use schematic diagrams in the science books because they
are simple as well as clear to understand.
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5. Enlist the importance of measurement.
The importance of measurement are listed below:
i. Measurement helps in buying and selling things.
ii. Preparation of food, beverage, medicine, etc. will be easier.
iii. Scientific experiments will have fewer errors.
Exercise
1. Fill in the blanks with an appropriate word.
pan balance measurement non-physical schematic diagram unit
a. The process of comparison of an unknown quantity with a
known standard quantity is called ……….
b. Happiness, sadness and anger cannot be measured. These
are
called ……. quantities.
c. Mass is measured by using ………….
d. Measurement can be expressed easily by the help of ..................
e. The diagram that is drawn using lines only to show the main
part of the apparatus is called …….
2. Write true for the correct and false for the incorrect statement.
a. Measurement is not necessary for scientific research,
engineering, business and trade.
b. Unit is a process where we collect information for the scientific
learning process.
c. Units of mass are kilogram, gram, pound, pau, dharni etc.
d. Mana pathi is used in the rural area while buying rice, wheat,
maize, etc.
e. Precise measurement is very important.
22 Oasis School Science and Technology -4 Approved by Curriculum Development Centre
3. Choose the best answer from the given alternatives.
a. What is the unit of mass?
kg meter litre second
b. What is used to measure the mass of the object?
clock measuring cylinder measuring tape pan balance
c. What measures the volume of the liquid?
clock measuring cylinder measuring tape pan balance
d. What is the unit of volume of liquid?
kg meter litre second
e. What device is used to measure time?
measuring cylinder ruler clock pan balance
4. Match the following.
Schematic diagram unit of volume
Unit clear and simple
Litre measures mass
Second standard reference form
Pan balance unit of time
5. Answer the following questions in one word.
a. What is the process of comparison of unknown quantities
with known quantities called?
b. Write down the unit of mass.
c. What measures the length of an object?
d. What kind of diagrams are used in the scientific learning
process?
e. What physical quantity is expressed in the foot?
6. Write any two differences between:
a. Mass and length
b. Volume and time
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7. Give reason.
a. Happiness is called a non-physical quantity.
b. Length is called a physical quantity.
c. We use units during measurement.
8. Study the given diagram and answer the following questions.
i. What physical quantity is measured by it?
ii. What is another device that can do the same work?
9. Answer the following questions.
a. What is measurement? List its importance.
b. What are units? Write with examples.
c. Define physical and non-physical quantities. Give examples.
d. What are schematic diagrams? Write down their properties.
e. What are the rules while drawing a schematic diagram?
10. Project work.
Draw the schematic diagram of the funnel, beaker, test tube and
tripod stand.
24 Oasis School Science and Technology -4 Approved by Curriculum Development Centre
UNIT Information and
2 Communication Technology
Introduction
Our ancestors have been using tools since ancient times. These tools
help us in many ways. Tools such as a hoe, spade and plough help us
in agriculture. Vehicles help us in transportation. Watermills help us
in grinding grains. Telephones and televisions help us in
communication. Smartphones and laptops help us in our studies. In
hospitals, ECG machines, stethoscopes, x-ray machines, etc. are used
to diagnose diseases. Technologies make our work easier and save
time. Watermill, dhiki, kol, etc. are the examples of local technologies.
Whereas computer, bus, crusher, generator, etc. are the examples of
modern technologies.
plough pani ghatta letters
train telephone computer
fig: some old and modern technologies
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Unit Means of Communication
2.1
Key terms and terminologies
1. Information: A set of facts is called information.
2. Communication: The process in which information is relayed or exchanged
between two or more parties is called communication.
3. Means of communication: The devices that help to send or receive information
are called means of communication.
4. One-way communication: The means of communication that provides
information for us but we cannot interact with the source is called means of
one-way communication.
5. Two-way communication: The devices that help us relay information and interact
with the sources right away are means of two-way communication.
Introduction
There are always some facts we may notice around us. The weather,
air, health, houses or movies may be topics of our interest. When we
learn the facts about the topics, we can analyse it. We can share what
we have learnt with other people, too. The process of collecting facts
and telling other people about them is the heart of information and
communication.
A set of facts is called information. We use our sense organs to collect
information from our surroundings. Information is very useful.
Reading books to learn people talk in phone to send
or receive information
26 Oasis School Science and Technology -4
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Advantages of information
Some of the advantages of information are listed below:
i. We become aware of our surroundings.
ii. We can plan our daily activities.
iii. We can be careful and avoid accidents.
iv. We can tell our thoughts to other people.
Activity
Let’s suppose you want to take part in a television
programme. How do you communicate? Discuss the
process with your friends.
Fact file
Communication always has two or more parties.
Resonable facts
Why are sense organs important?
Sense organs are important because they help us to collect
information.
We usually speak to our friends to share our opinions. We can write
letters or chat too. If we want to talk to our relatives who live away
from us, we can make a phone call. The process in which information
is relayed or exchanged between people is called communication.
Communication is very important in our daily life.
watching TV listening to the radio reading newspaper
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Aspects of communication
Important aspects of communication is listed below:
i. The government informs people about natural disasters, vaccination
campaigns etc. through radio and television.
ii. We can understand each other by communicating.
iii. Teachers can give information about homework and school
activities.
iv. It will make business and trade activities easier.
History of means of communication in Nepal
Letters were used to send information from one person to another in
ancient times. Letters were written and tied on the legs of the pigeon.
The pigeon would then deliver the letters. People themselves also
used to travel from place to place and relay information. The first post
office in Nepal was set up in 1878 BS. Under the system, the postman
used to deliver letters. The first newspaper was published in Nepal in
1901 BS, and thirteen years later the telephone service was also
launched. Nepal saw its first radio and television broadcasts in 1951
and 1984 respectively. Nowadays, radio, television, smartphones and
the internet are easily available throughout the country. Modern
technology has made communication easier, cheaper and faster.
postman pigeon with a letter newspaper artificial satellite
Fact file
The Gorkhapatra is the oldest newspaper in Nepal.
28 Oasis School Science and Technology -4 Approved by Curriculum Development Centre
Activity
Let’s suppose you are lost in a park. How will you contact
your parents? Discuss in a group.
Resonable facts
Why do people communicate?
People communicate to understand each other.
Means of communication
Letters, newspapers, radio, television, smartphones, etc. help us to
send and receive information. The devices that relay information are
called means of communication.
a group of people sharing reading the letter chatting on messenger
information
Means of communication are very important because:
i. They make communication easier and faster.
ii. They save time.
iv. They help us stay connected to our relatives at any time.
One-way and two-way means of communication
Based on how information is relayed, communication can be of two
types:
1. One-way communication
2. Two-way communication
We can listen to the news on radio and television but we cannot make
a direct reply to these sources of information. Similarly, movies, books
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and newspapers are also sources of information but we cannot interact
with them. The means of communication that give us information
without a way for us to interact with the sources are means of one-
way communication. It is very useful to relay information to a large
number of people at a time. Governments relay information through
TV, radio and newspapers. Weather forecast, job application etc. can
be found in the newspaper or on TVor the internet.
television radio newspaper
fig: means of one-way communication
Fact file
The ancient forms of communication are sound, acting,
songs, dance and symbols.
Activity
Listen to the news on radio or television and collect weather
information of a week.
Resonable facts
Why do governments use television and radio to relay
information?
Governments use television and radio to relay information
because they can send information to a large number of
people at a time.
We can use the telephone to talk to relatives. Smartphones can be
used for chatting or talking. We can use smartphones to make phone
calls to our parents during an emergency. These devices allow us to
exchange information with one another. The devices that help us
30 Oasis School Science and Technology -4 Approved by Curriculum Development Centre
relay information and interact with the sources right away are means
of two-way communication.
telephone smartphone messenger
fig: means of two-way communication
Summary
1. Humans have been using tools since ancient times.
2. Telephones, computers and televisions help in communication.
3. The process of collecting facts and sharing them with other people
is called information and communication.
4. A set of facts is called information.
5. The process in which information is relayed or exchanged
between people is called communication.
6. Governments inform people about natural disasters, vaccination
etc. via radio and television.
7. Modern technology has made communication easier, cheaper
and faster.
8. The devices that help us send or receive information are called
means of communication.
9. Based on how information is relayed, there are two types of
communication: one-way communication and two-way
communication.
10. The means of communication that provide information for us
without allowing us to interact with them are means of one-way
communication.
11. The devices that help us relay information and interact with the
them right away are means of two-way communication.
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Model Questions with Their Answer
1. Define communication.
Communication is the process of collecting facts and sharing
them with other people.
2. When was the post office started in Nepal?
The post office was started in Nepal in 1878 BS.
3. How many types of communication are there? What are they?
There are two types of communication: one-way communication
and two-way communication.
4. Newspaper is called a one-way means of communication. Why?
Newspaper is called a one-way means of communication because
we can get information from it but cannot interact with it directly.
5. How would you use smartphone?
I would use smartphone for the following purposes:
i. making phone calls.
ii. accessing the internet.
iii. taking part in online classes.
Exercise
1. Fill in the blanks with an appropriate word.
technology tools facts letters speak
a. The ability to use ……….. helps us in many ways.
b. Our life is made easier by …………...
c. The process of collecting …….. and telling other people is
called information and communication.
d. We usually ……….. to our friends to tell our opinion.
e. Information were sent from one person to another in ancient
times by ………..
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2. Write true for the correct and false for the incorrect statement.
a. Communication is very important in our daily life.
b. Governments inform people about the natural disaster,
vaccination etc. through radio and television.
c. The post office was started in Nepal in 1878 BS.
d. Modern technology has made communication difficult.
e. Newspapers are two-way means of communication.
3. Choose the best answer from the given alternatives.
a. What is information?
set of facts mobile set of communication internet
b. When was the post office started in Nepal?
1878 BS 1901 BS 1914 BS 1951 BS
c. Which one of the following is a means of one-way
communication?
newspaper messenger smartphone telephone
d. What is an example of two-way means of communication?
television radio smartphone book
e. Which one is an old means of communication?
television radio letter book
4. Match the following.
Set of facts 1951
Letter information
Telephone one-way communication
Exchange of information two-way communication
Radio Nepal communication
5. Answer the following questions in a word each.
a. What is the act of exchanging information called?
b. What is a set of facts called?
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c. Give an example of one-way means of communication.
d. Give an example of two-way means of communication.
e. When was Nepal Television established?
6. Write any two differences between:
a. Letter and telephone
b. Means of one-way and two way communication
7. Give reason.
a. We should communicate.
b. Book is called a one-way means of communication.
c. Messenger application is a means of two-way communication.
8. Study the given diagram and answer the following questions.
i. What is the person in the diagram doing?
ii. Is it a one-way or two-way means of
communication?
9. Answer the following questions.
a. What is information? Write the importance of information.
b. Whatiscommunication?Writeimportanceofcommunication.
c. What is ‘means of communication’?
d. Enlist the types of means of communication.
e. Define means of one-way communication. Give examples.
f. What are means of two-way communication? Give examples.
10. Project work.
Write a short note on the history of communication in Nepal.
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Unit Introduction to Computer
2.2
Key terms and terminologies
1. Computer: The device that works with the information is called a computer.
2. Input device: The device that sends information into the computer is called
an input device.
3. Keyboard: The keyboard is a flat board that has lots of keys.
4. Mouse: The mouse is a small, movable input device.
5. Storage device: The device that can store information is called a storage
device.
6. Output device: The devices that can display the information is called output
devices.
7. Monitor: The output device that displays videos and graphic information is
called a monitor.
Introduction
When we say computer, people generally think about a desktop.
However, the computer comes in various shapes, sizes and forms.
There are various kinds of computers. Some of them are very big and
some are very small. Some of them can do difficult tasks such as
flying rockets. Some do simple tasks such as addition and subtraction.
A digital clock, calculator, desktop, laptop, mac, tablet, smartphone,
iPhone, etc. are all computers. A laptop is a computer because it can
receive information, process it and store it. Thus, the device that
works with information is called a computer.
desktop computer laptop smartphone calculator
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History of computers
The abacus is said to be the oldest computer. It is not an electrical
device. It is used to do simple calculations. Charles Babbage made the
first computer. It was powered by a steam engine. The calculator is
the first electronic computer. Nowadays various forms of advanced
modern computers are available.
abacus computer made by Babbage modern super computer
Fact file
People blink less when they use the computer.
Activity
Practice turning on and shutting down the desktop
computer with the help of your teacher.
Resonable facts
Why is a computer called a smart machine?
A computer is called a smart machine because it can
process lots of information at once.
Parts of computer
There are many parts of the computer. Monitor, keyboard, mouse
and CPU are the main parts of the computer. Monitor and CPU receive
electricity from power cables. A VGA cable or HDMI cable connects
the monitor to the CPU. The mouse and the keyboard are connected
to the motherboard of the CPU by USB cables. Speakers, printers and
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projectors can also be connected to the CPU. When information is
sent to the computer, it is processed, stored and displayed. Computer
parts can be broadly divided into three categories: input devices,
output devices and storage devices.
Input device
The keyboard and the mouse can send information to the computer.
The device that sends information into the computer is called an input
device. Joystick, web camera, microphone, etc. are few other input
devices.
i. Keyboard
The keyboard is a flat board which has lots of keys. keyboard
It is connected to the motherboard. It can be used
to type letters, numbers and other symbols. We can
use it to play games as well.
Fact file
A standard keyboard has 101 keys.
ii. Mouse
The mouse is a small, movable input device. It is
connected to the motherboard. It usually has two
buttons and some of them have wheels. It appears
as a pointer in the monitor. We can use it to select
files and folders on the desktop. We can use it to
play games, too.
It is very easy to use a mouse. The index finger mouse
can be used for left click and scrolling. The middle finger can be used
for right click. We can use our palm to slightly move it on a mouse
pad. The pointer moves in the monitor.
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Activity
Practice using the mouse properly. Create a folder on the
desktop. Press right click in the desktop. Select new. Select
folder and press left click. A folder will be created in the
desktop.
System unit
CPU stands for central processing unit. It is also called a system unit.
It receives all the information from the input device. CPU has a
processing device and storage device. The CPU processes information,
so it is also called the brain of the computer. It also contains a hard
disk. It can store data for future use. The device that can store
information is called a storage device. A pen drive is a small removable
storage device. It is portable and easy to use. We can store photos,
videos and files in it. A floppy disk is a very old storage device. A CD
also stores songs and movies in it.
CPU mother board hard disk pen drive CD
Activity
Put a pen drive into the computer. Learn from your
teacher how to remove it safely.
Fact file
Russia once made a CPU that ran on water to solve
mathematical problems.
Resonable facts
Why is the CPU called the brain of the computer?
The CPU is called the brain of the computer because it
processes information.
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Output device
When information is processed by the CPU, it can be displayed by the
monitor. We can print files and photos from the printer. The devices
that can display the information is called output devices.
i. Monitor
The monitor can display visual information. The movement of
mouse pointer shows videos, files, photos, etc. on the monitor.
We can play games and watch movies on the monitor. The output
device that displays files, photos, videos and graphic information
is called the monitor.
CRT monitor LED monitor
ii. Speaker
Speakers can output audio information.
Activity
In the presence of your teacher, connect a mouse and a
keyboard to the CPU.
Uses of the computer
A computer can be used to compute information. It sees every bit of
information in the form of two numbers ‘0’ and ‘1’. The computer is a
multipurpose device. It can be used in the office to work. We can use
it to play games, too. It can be used to control satellites. We can use it
to watch movies, video chat, access information through the internet
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etc. The computer can do many types of work. It can process
information. Therefore, it is called a smart machine.
office personnels work on scientists control satellite people can play games in
computers through computers computers
Some common uses of the computer are listed below:
i. Computer is used in offices and banks to store information.
ii. It is used in industries to control machines.
iii. It is also used to control rockets and satellites.
iv. It can be used to play games and watch movies.
v. It can be used to create MS word documents.
vi. It helps us in mobile banking, online shopping, booking tickets
etc.
vii. It can be used for video chatting, online classes etc.
Fact file
The first computer looked like an oversized calculator.
Resonable facts
Why should we not hit computers?
We should not hit computers because they may break. We
can get an electric shock.
The computer is an electronic information processing device. It has
lots of delicate parts. It should be handled carefully. Some of the ways
of handling the computer are listed below:
i. Keep it in a cool and dry place.
ii. Use the Uninterruptible Power Supply (UPS).
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iii. Shut it down properly.
iv. Do not use it for a very long time.
v. Do not hit the keyboard, mouse, CPU and monitor.
vi. Do not pull any wires.
vii. Clean it regularly.
viii. Do not spill water or tea on computer parts.
ix. Use the pen drive carefully.
x. Use antivirus on the computer.
Activity
Unplug a keyboard from the CPU. Practice cleaning it
properly.
A dirty computer looks ugly. A keyboard collects dust and germs.
Dusty CPU heats up faster and its performance will be slower.
Therefore, we must keep our computers clean.
The best ways to keep our computer clean are listed below:
i. Do not use water to clean the computer.
ii. Use soft cloth to wipe the dust from the monitor.
iii. Use a brush to remove dust from the keyboard.
iv. Use a blower to remove dust from the CPU.
cleaning keyboard blowing away dust from
CPU
Computer and our health
The computer is a very useful device. We love to play games or watch
a movie on it. Office staffs work on it for hours. Using a computer for
a very long time can cause serious health problems.
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Some of the harmful effects and their solutions are listed below.
i. We blink less while using the computer. It will make our eyes dry
and it burns. We must blink our eyes regularly to keep them
moist.
ii. Our back is bent while using the computer. This will damage our
posture. Neck and back will hurt. Therefore, we must sit in a
good posture.
iii. We usually sit on a chair for a long time when using a computer.
This will disturb the flow of blood in our legs. It may cause
paralysis and heart attack. We must stand up every half an hour
and stretch our bodies.
iv. The brightness of the monitor must be balanced.
Resonable facts
Why should we stand frequently while using computers?
We should stand frequently while using computers so
that the blood can flow properly in our legs.
Summary
1. The device that works with information is called a computer.
2. Charles Babbage made the first computer that could do some
simple calculations.
3. Broadly, computer parts can be divided into three categories:
input devices, output devices and storage devices.
4. The device that sends information to the computer is called an
input device.
5. The keyboard is a flat board which has lots of keys.
6. The mouse is a small, movable input device.
7. The device that can store information is called a storage device.
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8. The device that can display information is called an output device.
9. The output device that displays videos and graphic information
is called a monitor.
10. The computer is a multipurpose device. It can be used in the office
to work. We can use it to play games, too.
11. Do not spill water or tea on computer parts.
12. Use soft cloth to wipe the dust from the monitor.
13. People usually sit on a chair for a long time when using computers.
This will disturb the flow of the blood in their legs. It may cause
paralysis and heart attack. We must stand up every half an hour
to stretch our bodies.
Model Questions with Their Answer
1. What is a computer?
The device that works with information is called a computer.
2. Write the full form of CPU.
CPU stands for Central Processing Unit.
3. Why should we stretch our bodies after sitting for half an hour?
We should stretch our bodies after sitting for half an hour because
this helps to supply blood all over the body.
4. How is Monitor different from mouse?
The monitor is differnet from mouse in following way:
Monitor is output device but mouse is an input device.
5. Why should we not use the computer for a long time?
We should not use the computer for a long time because:
i. It will hurt our neck.
ii. It will hurt our back.
iii. Our legs will be numb.
iv. Our eyes will be dry.
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Exercise
1. Fill in the blanks with an appropriate word.
calculator electricity information laptop computer
a. A ……. is a computer because it can receive information,
process it and store it.
b. Abacus is said to be the oldest ……….
c. The first electronic computer is ………...
d. The monitor and the CPU receive………… from power
cables.
e. The keyboard and the mouse can send ……… to the computer.
2. Write true for the correct and false for the incorrect statement.
a. A digital clock, calculator, desktop, laptop, mac, tablet,
smartphone, iPhone, etc. are all computers.
b. Charles Babbage made the first computer that could do some
simple calculations.
c. Joystick, web camera, microphone etc. are few output devices.
d. The device that can store information is called an input
device.
e. A CD also stores songs and movies in it.
3. Choose the best answer from the given alternatives.
a. What is the oldest computer?
pentium 1 super computer calculator abacus
b. Who invented the first computer?
Marconi James Watt Hawking Charles Babbage
c. Give an example of an input device.
joystick monitor speaker pen drive
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d. Give an example of an output device.
keyboard printer joystick mouse
e. What part of the computer is called the brain of the computer?
Monitor Key board Mouse CPU
4. Match the following.
Computer dry eyes
Mouse information processing device
Monitor input device
Pen drive output device
Watching on monitor storage device
5. Answer the following questions in a word each.
a. Who is called the father of the computer?
b. Write the full form of CPU.
c. Give an example of an audio output device.
d. What type of device is a keyboard?
e. Give an example of a handheld input device.
6. Write any two differences between:
a. Monitor and mouse
b. Keyboard and CPU
c. Hard disk and pen drive
7. Give reason.
a. Computer is called a smart machine.
b. The keyboard is called an input device.
c. The CPU is called the brain of the computer.
d. We should stand up and stretch our body every half an hour.
e. We should keep our computer clean.
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8. Study the given diagram and answer the following questions.
i. Write the name of the device shown in the
diagram.
ii. Write the use of this device.
iii. Where is it found on the computer?
9. Answer the following questions.
a. What is a computer? Write any three advantages of it.
b. What is a keyboard? Write down its function.
c. Define the mouse of the computer.
d. What is a system unit?
e. Define input device with an example.
f. What are output devices? Give two examples.
g. Define storage device with its examples.
h. What is a monitor?
i. How can we keep our computer clean?
10. Project work.
What might be the harmful effects of using a PC for a long time?
Discuss in a group and make a report.
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Unit Paint Software and Typing Software
2.3
Key terms and terminologies
1. Typing software: The software that helps us to practice typing is called
typing software.
2. Paint software: The software that allows users to draw and colour the
pictures is called paint software.
3. Tux paint: Tux Paint is a paint software.
4. Typeshala: Typeshala is a typing software.
5. Paint tool: A paint tool is a tool that can be used to draw lines, logos and clip
arts.
6. Line tool: A line tool is a tool that is used to draw solid lines and dotted
lines.
7. Shape tool: A shape tool is a tool that is used to create different types of
geometric shapes.
8. Text tool: A text tool is a tool that is used to type letters on the canvas.
9. Magic tool: A magic tool is a tool that is used to fill colours in ready-made
pictures.
Typing software
We need to type while writing books and essays, chatting and filling
forms. It is good for us if we can type correct and fast. We can practise
typing by ourselves. However, some software can help us to type
better and faster. The software that helps us to practise typing is called
typing software. Some of the common typing software used in Nepal
are Typeshala and Typing Tutor.
Advantages of typing software
i. It helps us to remember the position of keys.
ii. It helps to increase our typing speed.
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Activity
Press the left click on the desktop. Select new and press
left click on the new Microsoft document. Now, type a
paragraph about your family.
Fact file
The scroll lock is the least used key on the keyboard.
Resonable facts
Why do people use Typeshala?
People use Typeshala to increase their typing speed.
Paint software
People draw pictures on the canvas. They use MS paint
different colours, brushes and other tools to
create pictures. The process of drawing
pictures can be simulated on computers and
smartphones. We can draw and paint pictures
with paint software. The software that allows
48 Oasis School Science and Technology -4 Approved by Curriculum Development Centre
users to draw and colour pictures is called paint software. Microsoft
Paint, Tux Paint, etc. are popular paint software.
Activity
Download and install the Tux Paint application on your
computer or smartphone.
Tux Paint
Tux Paint is a paint software. It allows users to TUX software
draw different kinds of pictures and colour
them. We can use ready-made pictures and
photographs, too. It can also be used to create
logos.
Introduction of the tools to Tux Paint
1. Paint tool
The Paint tool can be used to draw lines, logos and clip arts.
2. Lines tool
The Line tool is used to draw solid lines and dotted lines.
3. Shapes tool
The Shape too is used to create different geometric shapes.
4. Text tool
The Text tool is used to type letters on the canvas.
5. Magic tool
The Magic tool is used to fill colours in ready-made pictures.
6. Eraser tool
The Eraser tool is used to delete unwanted parts of the image.
7. Save tool
The Save tool is used to store images in the hard disk.
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8. Rubber stamp tool:
The Rubber Stamp tool is used to insert readymade photographic
images on the canvas.
Home page of Tux Paint application software
Fact file
Tux Paint is designed for children of age 3 and above.
Resonable facts
Why is paint software popular?
The paint software is popular because it is easy to create
pictures.
It might be a bit difficult to use paint software at first. As a beginner,
we can practise by drawing a straight line. It follows the following
steps:
Step 1 : We should select the Paint tool. It looks like a brush on the
left side of the canvas.
Step 2 : We should select a brush from the bottom-left side of the
canvas.
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