Grade-3 Social Science, Term-2 Chapter-10 The Solar System

Chapter-10

Topic: The Solar System

  

Match these column:

A	B
Mercury, Venus, Earth and Mars	Longer than one year
Jupiter, Saturn, Uranus and Neptune	Uranus
Shape of orbits	Inner planets
Spin of Jupiter	10 hours
One day on Venus is	Elliptical
Planet that sleeps and spins	Outer planets

Ans-

A	B
Mercury, Venus, Earth and Mars	Inner planets
Jupiter, Saturn, Uranus and Neptune	Outer planets
Shape of orbits	Elliptical
Spin of Jupiter	10 hours
One day on Venus is	Longer than one year
Planet that sleeps and spins	Uranus

Fill in the blanks:

(28, craters, satellite, planetoids)

A-  Moons are also called as Natural satellite. 

B-  Moon takes 28 days to go around the Earth.

C-  Asteroids are also known as planetoids.

D- Sometimes meteors fall on the earth creating large craters and causing damage.

Sate True or False:

A-  Moon has no air. True

B-  Lunar month has 28 days. True

C-  We see only that part of moon that gets sunlight. True

Give one word for the following:

     1)   Second brightest object in the sky of Earth. 

     Moon

     2)   Pluto, Eris, Ceres, Haumea and Makemake.

     Dwarf Planets

     3)   A planet that has no moon. 

     Mercury /  Venus

     4)   A planet that has a maximum number of moons. 

     Saturn

     5)   Celestial body which is called a shooting star when it enters the earth's atmosphere.

    Meteors

     6)   The hottest planet. 

     Venus

     7)   The planet which is closest to the sun. 

     Mercury

     8)   The planet which is slowest in spinning.

     Mercury

     9)   The planet which is fastest in spinning.

     Jupiter

10)    Largest planet of solar system.

             Jupiter 

       11)    Large pieces of rock that are found in a belt between Mars and Jupiter. 

             Asteroids 

Define following:

Waxing, Waning, Phases of the Moon, Dwarf Planet

Waxing

Size of the moon seems to grow in size for two weeks till it becomes a full moon. This is called waxing.

Waning

After the moon is a full moon, it appears to shrink more and more, for two weeks, till it is hardly seen. This is called waning.

Phases of the Moon

The phases of the moon are the different shapes that the moon seems to make over about a month. 

Dwarf planet is a celestial body that -orbits the sun, is massive enough to be rounded by its own gravity, has not cleared the neighborhood around its orbit and is not a moon. For example-Pluto and Eris

Answer these questions:

Que- One part of mercury is extremely hot while the opposite side is very cold. Why?

Ans- Mercury spins very slowly. Therefore, the part facing the sun gets extremely hot while the opposite side which has no sun at all for a very long time gets very cold.

Que- Venus is the hottest planet. Why?

Ans- Venus has a thick layer of Clouds and air with gases that trap heat. Therefore, it is the hottest planet.

Que- Earth has life. Why?

Ans- Earth is ideally placed in the solar system. It has water and an atmosphere with gases like oxygen and nitrogen. This makes life possible on the Earth.

Que- What led scientists believe that at one time there might have been life on the Mars?

Ans- Mars has Seasons just like the earth. It has ice that melts in summer. This has led scientist to believe that at one time mass was warmer and there might have been life on this planet.

Que- What is the Eye of Jupiter?

Ans- There is a large red spot on Jupiter which is called the eye of Jupiter.  It is a giant storm that has lasted for hundreds of years. 

Que- What is the scooter of Neptune?

Ans- Neptune has a large white cloud that scoots or moves around quickly. It is therefore termed as scooter.

Que- Moon rises and sets in the sky. Why?

Ans- Moon moves around the Earth, therefore it appears to rise and set in the sky.

Que- What are Asteroids?

Ans- Asteroids are solar system bodies, made of rock and metal that orbit the sun.

They can vary in size from 10 metres to several kilometers.

Que- What are meteoroids?

Ans- Meteoroids are space rocks that are less than 10 meter wide.

Que- What are meteors or shooting stars?

Ans- When meteoroids enter the earth’s atmosphere and burn, they are called meteors.

Meteors are called shooting star as they look like stars moving fast in the sky.

Que- What is a crater?  Where can you see it?

Ans- Craters are approximately circular depression created by the impact of meteors. They can be seen on the surface of the planet, moon and other celestial bodies.

Que- Why does the moon has phases?

Ans- The Moon has phases because it orbits Earth.  

Moon does not shine by its light, but it lit-up by the sun. We see only the part of the moon that gets sunlight. Moon orbits the Earth and this causes the portion we see lit-up to change. 

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