Samacheer Kalvi 8th Science Solutions Chapter 8 Pdf

Samacheer Kalvi 8th Science Solutions Chapter 8 Pdf

Tamilnadu Board Samacheer Kalvi 8th Science Solutions Chapter 8: Tamilnadu State Board Solution Class 8 Science Chapter 8 – Universe and Space Science.

Samacheer Kalvi 8th Science Solutions Chapter 8: Overview

Board

Samacheer Kalvi
Class

8

Subject

Science
Chapter

8

Chapter Name

Universe and Space Science


Samacheer Kalvi 8th Science Solutions Chapter 8 Pdf

(I) Choose the best answer.

(1) Which of the following is a celestial body?

a) Sun

b) Moon

c ) Stars

d) All the above

(2) Mangalyaan was sent to Mars .

a) Moon

b) Mars

c) Venus

d) Mercury

(3) Chandrayaan -1 was launched on

a) 22nd October 2008

b) 8th November 2008

c) 22nd July 2019

d) 22nd October 2019

(4) Mars is called as Red planet.

a) Mercury

b) Venus

c) Earth

d) Mars

(5) Which of the following is the working principle of Rockets?

a) Newton’s first law

b) Newton’s second law

c) Newton’s third law

d) All the above

(6) Cryogenic fuels are stored at

a) room temperature

b) low temperature

c) very low temperature

d) very high temperature

(7) Apollo -8 was the first manned mission of NASA to go to the moon.

a) Apollo –5

b) Apollo -8

c) Apollo -10

d) Apollo -11

(II ) Fill in the blanks.

1 ) The study about stars and planets are known as Astronomy.

2 ) Our sun belongs to Milky Way  Galaxy.

3) Mars resolves around the Sun once in 687 days.

4) Mars Orbiter Mission is India’s first interplanetary mission.

5) Neil Armstrong was the first man to walk on the surface of the Moon.

(III) Say true or false. Is false, correct the statement.

1 ) The Sun and the celestial bodies form Solar system.

This statement is true.

2) Chandrayaan -1 was launched from Sriharikota.

This statement is true.

3) Mars is the smallest planet in the Solar system .

This statement is false.

Explanation :

In the Solar system,  Mars is not the smallest planet but instead,Mercury is the smallest planet in the Solar system.

4) PSLV and GSLV are India’s popular satellites.

This statement is true.

5) The propellant of a rocket is only in the form of solids.

This statement is false.

Explanation :

It is not relevant to affirm that the propellant of a rocket will only be in the form of solids but it can also be in the form of solids or liquids.

(IV) Match the following.

Chandrayaan Fuel
Mangalyaan Moon
Cryogenic First manned mission to the moon
Apollo -8 First man landing mission to the moon
Apollo -11 Mars

Answer The

Chandrayaan Moon
Mangalyaan Mars
Cryogenic Fuel
Apollo -8 First manned mission to the moon
Apollo -11 First man landing mission to the moon

(V) Answer briefly.

1 ) What are celestial objects?

Celestial objects refers to the stars ,the planets, the moon and several other objects such as asteroids and comets in the sky .The revolving of the sun and the celestial bodies around it, leads to the formation of the solar system.

2) Define galaxy.

‘Galaxy’ refers to a collection of billions of stars that are held collectively in the form of mutual attraction.’ Milky Way ‘ refersto a galaxy to which our sun belongs. The universe is formed by billions of such galaxies.

3) What are the objectives of Chandrayaan -1 ?

The objectives of Chandrayaan -1 are as follows :

  • To detect the probable chances of water on the Moon
  • To detect the components of matter on the Moon
  • To look for the presence of Helium -3
  • To construct an atlas of the Moon, which is 3 – dimensional
  • To investigate about the gradual transformations of the solar system.

4) List out the objectives of Mangalyaan.

The objectives of Mangalyaan are as follows:

  • To establish the technology that is essential for the interplanetary mission.
  • To analyze the exterior portion of Mars.
  • To examine the components of the atmosphere of Mars.
  • To render knowledge about the probable chances of life in the future and previous continuance of life on the planet.

5) What are Cryogenic fuels?

The fuels that are used in rocket engine are cryogenic fuels. Both the fuel or oxidizer are liquefied gases, in this kind of fuel and they are kept at a very minimal temperature . In this type of fuel ,there is no requirement of any ignition system. They shows their reaction on mixing and commence their own flame.

6) Name the Indians worked at NASA.

Kalpana Chawlaand Sunitha Williams are the two Indians who worked at NASA.

Explanation :

Kalpana Chawla

Kalpana Chawla was born in the state of Punjab and her birth date was 17th March 1962.  She joined the NASA in the year 1988. In 1997, she was selected to participate in the Columbia Shuttle Mission and  she was considered as the first Indian women to go to space and fetchsuch a record. But unfortunately,she succumbed to death the moment the shuttle broke down, when she was on her way to a second mission on the Columbia Shuttle.

Sunitha Williams

Sunitha Williams was born in USA and her birth date was 19th September 1965. In August 1998, she established her career as an astronaut. There are total two trips that she had made to the International space station. With a total space walk of 50 hour and 40 minute, she fetched a record of the longest space walking time by a female astronaut in the year 2012. She was also given the position of the crew of NASA’s Manned Mars mission.

(VI) Answer in detail.

1 ) What are the achievements of Chandrayaan- 1?

The achievements of Chandrayaan- 1 are as follows :

  • Chandrayaan -1 has discovered the existence of water molecules in the lunar soil.
  • The fact that, the moon was entirely molten once was affirmed by Chandrayaan- 1.
  • The images of the landing site of the US space- craft – Apollo -15 and Apollo -11 were recorded by Chandrayaan 1.
  • A high- resolution spectral data was provided by Chandrayaan- 1  on the mineralogy of the Moon.
  • The X-ray camera captured the presence of aluminium, magnesium and silicon.
  • In 75 days, there was transmission of more than 40,000 images by the Chandrayaan- 1 camera.
  • The obtained images of peaks and creators depicted that the Moon is comprised of craters.
  • The first images of the Earth was transmitted by Chandrayaan- 1 on the basis of its totality.
  • Discovery of large caves on the lunar surface. This large caves can serve as a shelter for humans on the moon.

2) Explain the parts of a rocket.

A rocket is a space vehicle that is primarily designed for the purpose of carrying people or equipment far away from Earth or out into space.

A rocket consists of four main parts or systems. They are:

  • Structural system
  • Payload system
  • Guidance system
  • Propulsion system

Explanation :

Structural system

Structural system mainly refers to the frame that covers the rocket. It is composed of materials such as titanium or aluminum but these materials are not so heavy and they possessan extreme hardness.  In order to provide stability during the time of flight, fins are attached to some rockets at the basal.

Payload system

Payload refers to the object that are carried by the satellite into the orbit. Payload is dependent on the rocket’s mission. The rockets are mainly modified for the purpose of launching satellites with an immense variety of missions such as communication,weathersurveillance ,spying , space exploration and as a space observatory. Special rockets are also established with an aim of launching people into the Earth’s orbit and on the surface of the Moon.

Guidance system

Guidance system are mainly designed for the purpose of guiding the rockets in its direction or path. Sensors, on- board computers, radars , and communication equipment’s are also included in the guidance system.

Propulsion system

The majority of the space in a rocket is taken up by this system. It is mostly comprised of fuel tanks, pumps and the combustion chamber. Liquid propulsion system and solid propulsion system are mainly the two major types of propulsion system.

3) Write a note on Apollo missions.

Apollo Missions was regarded as one of the most famous missions of NASA. These missions facilitated American astronauts to arrive on the Moon. It contained mainly 17 missions. Apollo -8 and Apollo -11 are most notable among them.  The first manned mission that went to the moon was Apollo -8 . Apollo- 11 was considered as the first’ Man Landing Mission’ to the moon. On 20th July 1969, it arrived on the Moon. Neil Armstrong was regarded as the first person to walk on the moon and he was also an American astronaut.

(VII)Higher Order Thinking Questions

1) We always see one side of the Moon. Why?

As, Moon  does not possess the light of its own, for this reason it reflects the sunlight. The time period of revolution around the Earth is equivalent to the time period of rotation of the Moon around its own axis . Due to this reason ,we always perceive only one side of the Moon.

Updated: November 22, 2021 — 4:56 pm

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