The Earth & the Solar System | Social Studies | Class 6 Chapter 1 (Complete Explanation)
The Earth & the Solar System | Social Studies | Class 6 Chapter 1 (Q & A)
Exercise A- Tick the correct option:
1) A constellation is a group of __stars __arranged in a particular shape.
2) The pole star always shines in the ___north__.
3) All the planets move around the Sun in a ___elliptical path__ (or) __elongated path_.
4) Which planet is made up of gases and liquid? _____Saturn___.
5) Which is the largest planet in the Solar system? ___Jupiter___.
6) Which is the farthest planet? ____Neptune___.
7) Which planet is known as the Evening Star? ____Venus___.
8) Tailed star is also known as a ____Comet____.
B-Fill in the blanks:
1) Our Earth is a part of the Galaxy called _____Milky Way____.
2) The Earth moves around the Sun from _____West___ to ___East___.
3) The planet with rings is ____Saturn___.
4) Meteors are commonly known as ____shooting___ Stars.
5) __Stars__ are self luminous bodies.
6) Moon is unlike the earth because it has no ___water___ and __air__.
7) The __Halley__ Comet appears after every 76 years.
C- State True or False:
1) A group of stars is called a constellation. T
2) The Milky Way is the only Galaxy in the Universe. F
3) The Solar system comprises of the sun, its eight planets and their satellites. T
4) Satellites are small celestial bodies revolving around a planet. T
5) Moon is a self luminous body. F
6) Asteroids are considered to be pieces of a planet. T
7) A comet is a small body which glows when it reaches near the Sun. T
D- Match the following: Answer -
1) Venus -----The hottest planet
2) Mars ------The red planet
3) Earth ------Watery planet
4) Saturn ----Rings around it
5) Pluto -----A dwarf planet
E- Answer the following questions in one word or phrase:
1) Who is known as the father of Indian astronomy?---- Aryabhatta (born in 476 AD)
2) What resulted after the big bang? Universe came into existence
3) Name some constellations. ---- Saptarishi Mandal [Ursa Major (Great Bear)], Orion, Leo, Gemini.
4) What is the fixed path of all planets called? ----Orbit
5) What is an object that revolves around a planet in its orbit called? ---Satellites
6) What satellite is placed in orbit with the help of rocket? ---- artificial satellite
7) Which tiny bodies revolve around the Sun between the orbits of Mars & Jupiter? ---Asteroids
8) Which is the only natural satellite of the Earth? ----Moon
F- Distinguish between them?
Q-What is the difference between a star and a galaxy?
Answer-A galaxy is a collection of stars. There can be billions of stars in a galaxy. All the stars you see at night, along with our sun, are all in the Milky Way galaxy.
Constellation & galaxy - A constellation is an apparent cluster of stars, while a galaxy is a real cluster of stars.
Comet - A body of ice, rock and dust that can be several miles in diameter and orbits the sun. Debris from comets is the source of many meteoroids.
Meteoroid - A small rocky or metal object, usually between the size of a grain of sand or a boulder that orbits the sun. It originates from a comet or asteroid.
Meteor - A meteoroid that enters the earth’s atmosphere and vaporizes. Also called a “shooting star.”
Meteorite - A meteor that hits Earth without burning up in the atmosphere.
Moon / Satellite - A body orbiting a planet.
Planet - A body orbiting a star.
Star - A ball of burning gas (Hydrogen & Helium). Every second, 600 million tons of hydrogen is being converted into helium. This reaction releases a tremendous amount of heat and energy.
Solar System - A collection of planets and satellites orbiting a star or stars.
Galaxy - A collection of stars.
Universe – Everything (including Space, Time, matter & Energy) is called Universe.
G- Give reasons:
1) The Earth is called as blue planet.
Answer- The three-fourth of the earth's surface is covered with water bodies. And when looked from the space it appears blue due to those water bodies. That is why it is also known as the Blue planet.
2) We see only one side of the Moon.
Answer- The moon takes same number of days to make a revolution and a rotation. Due to this, only one face of moon is visible to us.
3) Life is not possible on the Moon.
Answer-Moon does not have any water or atmosphere. Therefore, there is no life on it.
4) Earth is a unique planet.
Answer-Earth is the only known planet where life exists. Earth has the right conditions for supporting life. Water and air are available on earth and they are essential for life. Earth has the right temperature for living beings. Hence, the Earth is called a unique planet.
H- Answer the following questions in brief:
1) What is Milky Way?
Answer-The Milky Way is the galaxy that contains our Solar System. The Milky Way has several satellite galaxies and is part of the Local Group of galaxies, which form part of the Virgo Super cluster, which is itself a component of the Laniakea Super cluster.
2) What is a constellation? Give an example?
Answer- In the night sky, you can see different patterns formed by groups of stars. Such a pattern of stars is called constellation. Examples are Saptarishi Mandal [Ursa Major (Great Bear)], Orion, Leo, Gemini.
3) What is the importance of the Sun in our Solar System?
Answer-The system formed by the Sun, eight planets, satellites, asteroids and various other celestial bodies is called the Solar System. The sun is at the centre & the head of the solar system. It controls the movement of the bodies by its gravitational pull.
4) What is a celestial body?
Answer-The Sun, the Moon, planets, stars and other bodies in the Universe are called celestial bodies.
5) Why Venus is the hottest planet in the Solar System?
Answer- Venus is the hottest planet in the Solar System due to the green house effect in its atmosphere.
6) What are satellites?
Answer- Some celestial bodies keep on moving around a planet. They are called satellites.
I-Answer the following questions in detail:
1) What do you understand by stars?
Answer- Some celestial bodies are very big and hot. They are made up of gases. They have their own heat and light. A celestial body which emits its own heat and light is called a star.
2) What is the Solar System made of?
Answer- The system formed by the Sun, eight planets, satellites, asteroids and various other celestial bodies is called the Solar System. The Sun is at the centre of the solar system.
3) Why the Earth is called a unique planet?
Answer: Earth is the only known planet where life exists. Earth has the right conditions for supporting life. Water and air are available on earth and they are essential for life. Earth has the right temperature for living beings. Hence, the Earth is called a unique planet.
4) What are asteroids and where are they found?
Answer- There is numerous small bodies which move around the Sun. These are present between the orbits of Jupiter and Mars. These are called asteroids.
5) What are phases of Moon?
Answer-
New Moon - The first phase of the moon. In this phase, the moon is completely dark since we can’t see the side that the sun is shining on.
New Moon - The first phase of the moon. In this phase, the moon is completely dark since we can’t see the side that the sun is shining on.
Crescent Moon- The second phase of the moon. In this phase, we can see sunlight reflecting off only about one quarter of the moon’s surface that faces us.
Quarter Moon- The third phase of the moon. In this phase, we can see sunlight reflecting off half of the moon’s surface that faces us.
Gibbous Moon- The fourth phase of the moon. In this phase, we can see sunlight reflecting off three quarters of the moon’s surface that faces us. It’s not a full moon yet, but it’s getting there.
Full Moon- The fifth phase of the moon. In this phase, we can see sunlight reflecting off all of the moon’s surface that faces us. In this phase the moon appears round and completely lit up.
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