Samacheer Class 6 Social Science - The Universe and Solar System

1. A. Jupiter
2. B. Saturn
3. C. Uranus
4. D. Neptune

(b) Saturn
C. Circle the odd one out

D. Match the following

1. – c
2. – d
3. – a
4. – e
5. – b
E. (i) Consider the following statements
1. Venus rotates from east to west.
2. The Tropic of Cancer faces the Sun on June 21.
3. Mars has rings around it.
Choose the correct answer using the codes given below.
(a) 1 and 2
(b) 2 and 3
(c) 1, 2 and 3
(d) 2 only
(a) 1 and 2
(ii) Consider the following statements
Statement I : Earth is called a watery planet.
Statement II. : The rotation of the Earth causes seasons.
Which of the statement(s) is/are true?
(a) I is true; II is wrong
(b) I is wrong; II is true
(c) Both the statements are true
(d) Statements I and II are wrong.
(a) I is true; II is wrong
F. Name the following

Inner or Terrestrial Planets
Mercury, Venus, Earth, Mars.
They are comparatively smaller in size.
They are composed of rocks. The surface of the inner planets has mountains, volcanoes and craters.
None of the inner planets have rings orbiting them
Outer Planets or Jovian Planets, or Gaseous Giants
Jupiter, Saturn, Uranus, Neptune.
They are huge in size.
Most of them are made of gas.
All of the outer planets have rings orbiting them.

Effects of Rotation:
It is the spinning movement of the Earth on its axis
The time taken by the Earth to complete one rotation is called a day.
The rotation of the Earth causes day and night, As the Earth is spherical in shape, only one half of it is illuminated by the Sun at a time.
The other half remains dark.
The illuminated portion of the Earth experiences day, whereas the darkened part of the Earth experiences night.
Effects of Revolution:
It is the movement of the Earth around the Sun on its elliptical path.
The Earth takes 36514 days to complete one revolution.
It revolves around the Sun at a speed of 30 km per second.
The remaining quarter day is added once in every four years in the month of February.
The inclination of the Earth on its axis and its revolution around the Sun cause different seasons.

Earth is the most suitable planet to support life. It has three major components that we call the realms of the Earth lithosphere, hydrosphere, and atmosphere.
(i) Lithosphere: The word lithosphere is derived from the Greek word Lithos, which means rocky. The Lithosphere is the land on which we live.
(ii) Hydrosphere: The word Hydro means water in Greek. The hydrosphere consists of water bodies such as oceans, seas, rivers, lakes, ice caps on mountains, and water vapour in the atmosphere.
(iii) Atmosphere: The word Atmo means the air in Greek. The atmosphere is the envelope of air that surrounds the Earth. Different types of gases make up the atmosphere. The major gases are Nitrogen (78%) and Oxygen (21%).
(iv) Biosphere: The narrow belt of interaction among the lithosphere, the hydrosphere, and the atmosphere, where life exists is known as Biosphere. Bio means life in Greek. It consists of distinct zones.
J. Picture Study

Mercury

Question b.
Which is the largest planet?
Jupiter
Question c.
Which is the farthest planet from the Sun?
Neptune
Question d.
Which is the second smallest planet?
Mars

Uranus
Question b.
What is the colour of the planet?
Green
Question c.
Why is it of this colour?
Due to the presence of Methane

STUDENT ACTIVITY
K. Solve the puzzle

Across:
2. A dwarf planet.
3. Equal days and nights.
7. I am a gas found in the Sun.
8. I appear once in 76 years.
Down:
1. I am the morning star.
2. India’s first moon mission.
4. I have two natural satellites.
5. I am the farthest planet.
6. An imaginary line passing through the centre of the Earth.

1. A. I is true, II is wrong
2. B. I is wrong, II is true
3. C. Both the statements are true
4. D. Both the statement are wrong

(d) Both the Statement are wrong