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Look and read
Sun
Mercury
Venus
W
e live on a planet. It is the
planet Earth. Our planet
Earth goes round the Sun with
eight other planets. They are the
planets Mercury, Venus, Mars,
Jupiter, Saturn, Uranus, Neptune
and Pluto. Mercury is the planet
nearest to the Sun. Pluto is the
planet furthest from the Sun.
The Earth is between the planets
Venus and Mars. The Sun and
the nine planets make up our
Solar System. The path of the
planets round the Sun is called
the orbit.
Mars
Jupiter
Uranus
Pluto
Neptune
orbit
The Sun is the star closest to us.
All the other stars we see in the
sky are very far away.
Which are the three planets nearest to the Sun?
Of these three planets which is nearer to the Sun, Venus or the Earth?
Between which planets is the Earth?
What do you call the path of the planets round the Sun?
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Saturn
World of Science
Have you seen something shining
very brightly like a star in the sky
sometimes before sunrise and
sometimes after sunset? It is not
a star. It is the planet Venus.
Earth
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Read and answer
Why do you always come down
when you jump up? It’s because
the Earth’s gravity pulls you down.
If there was no gravity and you
jumped what would happen then?
You would begin to float in the air.
Far above the earth, in space, there
is no gravity. Therefore, when
astronauts go into space in
spacecraft they can float.
Sometimes it’s very hot in space
and sometimes very cold. There is
no air in space. Therefore
astronauts wear a special suit when
they float in space. This suit gives
them air to breathe and protects
them from the Sun’s rays and the
cold.
Are these statements true or false?
1. The astronauts can float on the Earth.
2. The astronauts can float in space because of the special suits they wear.
3. You cannot float on the earth because of the gravity.
4. You can float in space without a space suit but it is dangerous.
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Read and find
Energy is needed to do any kind of work.Things that supply energy are called
sources of energy. There are many types of energy like light energy, heat
energy and electrical energy. There are many kinds of things that supply
energy. Look at the pictures below. What kinds of energy do they need? What
things supply the energy?
PETROL
sunlight
food
petrol
electricity
firewood
batteries
gas
I get energy to glow
from ............... .
I get energy to grow
from ...............
I get energy to turn
from ............... .
I get energy to cook
from ............... .
I get energy to run
from ............... .
I get energy to burn
from ............... .
Where does a tree get energy to grow?
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We get energy to
play from ............... .
It gets energy to grow from sunlight.
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Read and answer
Today we have many ways of
sending messages to people who
are far away. But how did
people in early times send
messages over long distances to
other people?
The pictures illustrated here
show some ways in which
people used to send messages in
early times.
In early times ...............
People used to send messages with the help of pigeons.
People used to send messages with the help of smoke signals.
People used to send messages by waving flags of different colours.
People used to send messages by beating on drums.
People used to send messages with the help of messengers on horseback.
Which of the above is not shown in the picture?
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Read
All living things – plants, animals and humans – need food to stay alive. Only plants
are able to make their own food. They make their food with the help of sunlight,
water and air. Animals and humans have to eat plants or other animals for their food.
This food link between plants, animals and humans is called the food chain.
Look at the picture of the food chain given below. Who or what is eaten by
whom?
Rabbits are
eaten by foxes.
Grass is eaten
by rabbits.
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Look and read
Today there are many ways people can
communicate with other people far away.
Modern methods of communication are
easier and faster than they were in the past.
For example, if we want to communicate
with a friend far away we can telephone
the person or send a fax message to him or
her. If we have a computer we can send an
e-mail.
[email protected]
[email protected]
Today we can send and receive messages
from any part of the world with the help of
communication satellites.
Communication satellites in space receive
messages from one part of the world and
send them to another part. Dr. Arthur C.
Clarke is the first person to suggest the idea
of using satellites for long distance
communication.
Satellite
Receiving
Ground
Station
Earth
Answer the questions
Name three different ways of sending messages.
Which of these is the fastest? Why?
Which of them is the cheapest?
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Read
If you want to listen to a cricket
match played in a far away place
you turn on the radio. But if you
want to listen and see the match
you turn on the television.
Television helps us to see and hear
events as they happen in places far
away from us.
The television camera “sees” the picture. It
turns the picture into a series of electrical
signals. The television station receives these
signals through a receiving antenna in the
television tower. The signals are again sent out
to the whole country through a transmitting
antenna. The antenna of our television set at
home picks up the signals. Inside the television
set the signals are turned into pictures again.
Read and match
1. You cannot see a match by listening to the radio.
2. The signals are received through the receiving antenna.
3. The signals are picked up by the television antenna.
4. The transmitting antenna sends out the signals.
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Inventors and Inventions
Aeroplane
In 1903 the Wright brothers made
the first powered flight in an
aeroplane. The flight lasted only
twelve seconds. The plane looked
very different from aeroplanes today.
Car
Karl Benz invented the first motor
car in Germany in 1886. It was
not like the cars we see today.
Radio
Guglielmo Marconi invented the
radio in 1901. He sent his first
message across the Atlantic Ocean
from Cornwall in England to
Newfoundland in Canada.
Telephone
Alexander Graham Bell invented
the telephone in 1875. He found
that he could send messages along
a wire using electricity.
1. Who invented the radio?
2. Who invented the first car?
3. Who made the first powered flight in an aeroplane?
4. Where was the first car invented?
5. Where was the first radio message sent to?
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We get electricity from
water. The water flows
to a reservoir.
I work by electricity.
This is how we get
electricity.
B
When the gate is opened the
water pours down a tunnel into
the power house. Inside the
power house the water turns a
large wheel called a turbine.
The turbine turns a generator
which gives us electricity.
A
The dam holds back the
water in the reservoir.
D
C
This electricity is
used by people
at home.
The electricity is sent to homes
through electric wires on pylons.
E
F
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I kept a burning candle on a dish
of water. I covered it with a glass
jar. When the candle burned it
used some of the air in the jar.
The space left by the air used by
the candle was filled with water
from the dish. The water level
inside the glass went up.
I put some water into a
kettle. I let the kettle boil.
I held a piece of glass to
the steam. Droplets of
water appeared on the
glass.
Warning: Be very careful if
A
B
you try this experiment. Keep your hands away from the steam.
I had a branch with leaves on it.
I covered it with a polythene bag. I left it
for a little while and then looked at it.
I could see water droplets inside the
bag. This shows that plants give out
water when they breathe.
1. What happened when Kusum covered a candle with a glass jar?
2. What happened when Meena held a sheet of glass over steam?
3. What happened when Nizar covered a branch with a polythene bag?
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electric fan
light bulb
floor polisher
refrigerator
clock
1
I have a face and two hands. One hand is
long, it moves quickly and the other hand is
short, it moves slowly. I make a sound, “tick
tock”. What am I?
2
I run on electricity. I work very hard when it is
hot. I have four wings. These move round and
make the air cooler. What am I?
3
I run on electricity. I help to keep the floor
clean and shiny. I make a noise when I am
working. I have a long handle. What am I?
4
I run on electricity. I am made of glass. I help
you to see in the dark. I am made in different
colours and sizes. What am I?
5
I run on electricity. I am very cold inside. I
keep food and drink cold and fresh.
What am I?
1. Which item does not run on electricity?
2. What keeps food cold?
3. What helps you to see in the dark?
4. What makes the floor shiny?
5. What keeps you cool in hot weather?
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Fill me up and plug me in,
You must be patient you see.
Wait until the water boils,
And you can make a cup of tea.
I’m a ..............
When you hear me ringing,
Lift me up and say “Hello”.
You can chatter, gossip, laugh and sing,
With all the people that you know.
I’m a ..............
Click my switch and turn me on,
Now just look at me!
There are lots of funny programmes,
Because I am your great TV!
Click on my mouse to start me,
Just look at what I can do.
I can help you do your homework,
And you can play games on me too!
I’m a ..............
I can make clothes look as good as new,
Just plug me in and wait.
All your clothes will be so very neat,
No creases, all nice and straight.
I’m an ..............
1. What do we use a telephone for?
2. What do we use a kettle for?
3. Do you like to watch television?
4. What do you use to keep your clothes nice and neat?
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:KDWDUHWKH\WKLQNLQJ"
lever
computer
camera
pump
The heart is like a ............... . It pumps blood round the body.
The brain is like a ............... . It helps us to think.
The arms are like ............... . They help us to lift things.
The eye is like a ............... . It helps us to see things.
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All foods contain nutrients. Our bodies need nutrients to make them healthy and give them
energy. Nutrients can be divided into different types. Look how they are divided up in the
chart below.
Proteins
These foods give us energy to work and play.
There are two kinds of carbohydrate; starch
and sugar. Rice and potatoes contain a lot of
starch. Sugar gives us energy but too much
sugar is bad for your teeth and can make
you fat.
These foods help us to keep our bodies fit
and strong. There are two kinds of protein;
animal protein and plant protein. Fish and
meat are high in protein. People who don’t
eat fish or meat can get their protein from
soya, green peas, nuts, milk, etc.
s
in ls
m ra
ta ne
Vi Mi
d
an
Fats and
Oils
Carbohydrat
Carbohy
drates
drat
es
Carbo
hydra
tes
Proteins
As well as all of
these different
foods you must
remember to drink
plenty of water
every day.
A balanced diet
Vitamins and Minerals
Fats and Oils
These foods help to keep us healthy. We
need them to keep our bones and teeth
strong. Fruit and vegetables give us vitamins,
energy and fibre. They don’t make us fat.
Butter, cheese and coconut all contain high
levels of fat.
Although these foods give us a lot of energy,
too much fat in our diet can cause heart disease.
1. What are the main things we
need for a healthy diet?
3. Is too much fat good for you?
2. Are sweets good for you?
5. Is fruit good for you?
4. Is fish good for you?
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