Class 4- Science Remedial (Earth & Its Neighbours)

Hi All, 

Hope you are doing great!!😊😊

Today we will be learning about Earth and its neighbours. The Earth is one of the eight planets orbiting the sun. But it is different from other planets because it has life. It has many heavenly neighbours. Let us know about them.

After reading this blog, you will know about:

·      The sun,

·      The earth,

·      Planets and the solar system,

·      Satellites,

·      Constellations.

The Sun:

The Sun is a star. It is the star around which the Earth and other planets revolve. In a way, we can say that the Sun is the head of Solar Family or Solar System. The Sun is a medium sized star and of average brightness as compared with millions of other stars. The Sun appears to be larger and brighter because it is much nearer to the Earth than any other star. Thus, the star nearest to the Earth is the Sun.

The Earth:

Earth is the only planet in our Solar System that has water in liquid form, Oxygen, and supports life. Earth takes 365-1/4 days to revolve around the Sun and takes 24 hours to rotate about its own axis.

What are the different layers of the Earth:

Our Earth consists of four different layers namely:

• Crust
• Mantle
• Outer Core
• Inner Core

1.     Crust:

   The crust is the outer layer where we live. It is a thin layers of mostly solid rocks. It    includes the soil.

2.     Mantle:

   Mantel lies below the crust and is made up of very hot rocks. Sometimes, this hot      liquid oozes out from cracks, this is called a volcano and the hotter molten rock is called lava.

3.    Outer Core:

   The outer core is liquid.

4.    Inner Core:

   It is the innermost part of the earth. The inner core is solid.

 Now let us watch this video to understand the layers of the earth. 

The Solar System

Planets

1. Mercury- Mercury is the smallest planet in our Solar System. It is closest to the Sun.     Mercury is very hot during the day and has a very thin atmosphere. Hence, heat is quickly lost at night and it becomes very cold.

2. Venus –   Venus is the hottest planet in our Solar System. It is brightest of all the planets in the night sky, so it is also called morning and evening star as it appears in the eastern sky before Sunrise and in the western sky after Sunset. It is closest to the Earth.

 3. Earth –   Earth is the only planet in our Solar System that has water in liquid form, Oxygen, and supports life. Earth takes 365-1/4 days to revolve around the Sun and takes 24 hours to rotate about its own axis.

4. Mars –     Mars a reddish planet, the red color is due to the presence of red dust on it.

5. Jupiter –   Jupiter is the biggest and the fastest spinning planet in our Solar System. 

6. Jupiter, Saturn, Uranus and Neptune, all have rings. Saturn's rings are most brilliant.    

7. Neptune is the farthest planet from the sun. It has a great dark spot.

Let us watch this video to understand the Solar System 

Let us now learn about the movements of the earth:

Rotation of the earth

Spin a bangle on any table top. Do you see any imaginary line in the spinning bangle? This imaginary line that we see is called axis.

The earth also spins on its axis. This movement is called rotation. The earth spins from west to east and complete its one rotation in approximately 24 hours. We don’t feel earth spinning because everything including us is spinning along the earth at the same speed. It is the earth's rotation that causes day and night.

Why do we have day and night?

Earth is always moving on its axis which allows sunlight to shine on different parts of the earth. The area of the earth facing the sun receives sunlight, experiences day and the area of the earth which does not receive sunlight, experiences night. At all time, half portion of the earth is lighted by the sun and half of the earth remains in darkness.

Revolution of the earth

As the earth rotates, it also moves around the sun in a fixed path. This fixed path in which earth moves around the sun is called Orbit. Movement of the earth around the sun in its fixed orbit is called revolution. Earth takes one year to complete one revolution. Earth is slightly tilted from its axis. Earth tilt’s and its movement around the sun in its fixed path causes seasons.

Let us now watch this video to understand revolution of the Earth:

  

Satellites:

A satellite is a heavenly body that revolve around planets. Some planets have their own satellites. The moon is the natural satellite of the earth. It revolves around the earth in an orbit. It takes around 28 days to revolve around the earth.

Moon does not have its own light. Moonlight in reality is the reflected sunlight. The sunlight shines on the moon and moon reflects it towards the earth.

The earth has other satellites too. These satellites are machines made by man and are called artificial satellites. These satellites are used by people to learn more about space and earth. The Russia's (Erstwhile USSR's) Sputnik-1 was the first artificial satellite to enter the earth's orbit. Aryabhata was India's first artificial satellite. Bhaskara, Rohini, Insat 1A, Insat 1B, Insat 1C are some other Indian satellites.

Constellations :

A group pf stars with a definite pattern is called a constellation. There are 88 known constellations. Most of these were named in ancient times. Each constellation has a particular pattern. Ursa major or Great Bear, Orion or Hunter are some of the constellations.

Now solve this worksheet with the help of your knowledge and your textbook.

CLASS - 4                  THE EARTH AND ITS                       REMEDIAL WORKSHEET

                                                    NEIGHBOURS

1. FILL IN THE BLANKS

a)    Earth is also called ________________ planet due to presence of water on it.

b)   ____________ is also called __________ planet due to presence of red dust on it.

c)    Sun has its own __________ and _____________.

d)   Moon takes _________ days to revolve around the earth.

e)    _____________ is an imaginary line that divides the earth into two hemispheres.

2. GIVE ONE WORD FOR THE FOLLOWING:

a)    An imaginary line running from North Pole to the South Pole.

b)   A group of stars with a definite pattern.

c)    A heavenly body that moved around a star with no heat and light of its own.

d)   Heavenly bodies that revolve around planets.

3. STATE TRUE OR FALSE

a)    Jupiter, Saturn, Uranus and Neptune all have rings.

b)   Mercury is the farthest planet from the sun.

c)    Earth completes one revolution in 365 ¼ days.

d)   The Sun and the eight planets and their satellites form the constellation.   

4. MATCH THE FOLLOWING

a) Biggest & Fastest Spinning Planet                         1. Hunter

b) Outer layer of the Earth.                                2. Jupiter

 c) A Constellation                                                  3. Pluto

d) Dwarf Planet                                                       4. Crust

5. ANSWER THE FOLLOWING:-

a) Write the difference between rotation and revolution.

b) Write the difference between natural satellites and man-made satellites.

6. CHOOSE THE CORRECT OPTION:

A. It is winter in Northern Hemisphere and___________ in Southern hemisphere.

a. Autumn             b. Spring            c. Winter           d. Summer.    

B. Rotation causes _____________ on Earth.

a. Winter                         b. Day & Night c. Summer                 d. Seasons.

C. Natural Satellite of the Earth. 

a. Sun                      b. Star                c. Moon             d. Mars.    

7. GIVE REASONS WHY

a) Venus is also called a morning star or evening star.

b) Without sun there would be no life on the earth.

8. ANSWER THE FOLLOWING:-

a) Moon does not have its own light. Yes or No. Explain your answer.

b) Describe how an Axis is different from the Equator.

9. Name & Label the diagram.