1.Keywords
1.Big bang: Some 13.7 billion years ago, the universe was a big burning ball - like structure. Due to heavy pressure it burst away with a great explosion, which was the beginning of the birth of several celestial bodies. This was Big Bang
2.Grid: A network of latitudes and longitudes drawn on the globe is called Grid.
3.Gondwana: The broken part of supercontinent Pangea that consists of present South America, Africa,Madagascar, India, Arabia, Malaysia, East-Indies, Australia and Antarctica
4.Laurasia: The broken part of supercontinent Pangea that consists of present North America, Greenland Eurasia and north of Indian sub-continent.
5.Time zones: Time zones are the areas which the world is divided into a particular number of hours behind or ahead of GMT. There are 24 time zones in the World.
6.Standard time: Some countries choose a uniform time along one of the meridians that pass through their territory. This time is called standard time.
Short Answers:
1.What do you mean 'Pale Blue Dot' ?
A.
'Pale Blue Dot' was inspired by an image of Earth pointed by a scientist Carl Sagan.
2.What is environmental crisis?
A.
1.Reckless exploitation of the Earth like destruction of forests, rivers, hills, animals and even fellow men is called environmental crisis.
2.This resulted in global warming and poisoning of our soils, water and air.
3.What is called geocentric theory?
A.
1.Initially, people thought that earth was firm and stationary and all others went round it.
2.Ptolemy proposed this as Geocentric theory without any change.
4.What is called sun centric theory?
A.
1.Copernicus proposed Sun Centered theory
(Heliocentric System).
2.According to this the Earth is not in the middle of solar system, that it is actually moves around the Sun and that the sun itself is also constantly moving.
5.What are the Indian books are reveals about the universe?
A.
1.Vedanga Jyotisha, Surya Sidhanta and Bhagavata Puranas etc.,
2.They reveals a lot of information with respect to Universe. Eclipses, transits, occultations and infinite nature of universe.
6. What is the plane of the Orbit?
A.
The path of the Earth around the Sun is on a uniform plane which is called the plane of the Orbit.
7. Into how many parts the Pangaea divided?
A.
Pangaea was divided into:
1.Laurasia (present North America, Greenland and all of Eurasia, North of Indian subcontinent)
2.Gondwana - land (present South America, Africa, Madagascar, India, Arabia, Malaysia, East Indies, Australia and Antarctica).
8.Write about the evoluation of the Earth?
A.
1.Earth began to form around four and a half billion years ago.
2.It began as a ball of swirling dust and clouds, and passed through a molten stage, very hot and constantly bombard by massive rocks and other materials from the space, grew in size.
3.The Earth was so hot and molten (in hot liquid form) therefore heavier substances formed as molten core, lighter substances rose and formed an upper crust.
4.The outer crust wrinkled, forming ridges (mountains) and basins (oceans)
5.It didn’t have Oxygen, it took a long time for the air we breath to develop.
6.Then, life appeared in the oceans. It slowly evolved into diverse plants, animals, and human beings.
9.Describe about the interior of the Earth.
A.
The earth is made up of three main layers :
1. Crust
2. Mantle
3. Core
1.Crust: We live on the outer part of the earth which is called the crust. This layer goes up to a depth of 100kms. The crust consists of various kinds of rocks.
2.Mantle: It exists at the depths from 100 kms to 2,900 kms. This consists mainly of chemicals called silicates.
3.Core: It exists at the depths from 2,900 kms to 6,376 kms. It is composed of dense and heavy substances like iron and nickel.
It is divided into two sub layers.
Outer Core: 2,900 to 5,100 kms composed of liquid metallic material like nickel and iron.
Inner Core: The solid inner core (5,100 – 6,376 kms) is made up of Iron compounds and heavy substances like gold.
10.How can you say earth is still very active?
A.
1.In many regions the earth’s crust enters into the mantle and once again becomes molten.
2.The crust still being changed by earthquakes, volcanoes, subduction of land and rise of mountains due to processes happening deep inside the earth.
3.This constant process of formation and destruction of the crust explains that our Earth is still very active.
11.What is called Pangaea?
A.
1.Pangaea was a massive land part of the earth that existed 220 million years ago, which was not divided into the present continents.
2.It is a hypothetical continent from which present continents originated by the drift of Mesozoic era to the present.
12.What were the land masses located on both sides of the Tethy's Sea?
A.
The land mass to the north of the Tethys Sea was Laurasia and to the south of it was Gondwana land.
13.Write about the Continental Drift Theory ?
A.
1.Continental Drift theory was proposed by Alfred Wagener, a German meteorologist and geophysicist.
2.
14.What are called Longitudes?
A.
1.The word 'Longitude' is derived from the Latin word 'longitudo' meaning length.
2.They are the semicircles connecting pole to pole.
3.These are drawn based on Prime meridian.
3. Every longitude cuts across every latitude.
4. There are 360 longitudes.
15.What are called Latitudes?
A.
1.The word 'Latitude' is derived from the Latin word 'latitudo' meaning 'width'.
2.They are the parallel circles from the Equator.
3. These are drawn based Equator.
4. There are 180 latitudes.
16.Name some important latitudes.
A.
1. Equator (0°)
2. Tropic of Cancer (23½°N)
3. Tropic of Capricorn (23½°S)
4. Arctic circle (66½°N)
5. Antarctic circle (66½°S)
6. North pole (90°N) and
7. South pole (90° S).
17. What is Equator?
A.
The imaginary horizontal circle that drawn on the Earth exactly in the middle, at equal distance from the north and south poles is called the Equator.
IMPROVE YOUR LEARNING:
1.Look at the map of India in an Atlas and identify latitude and longitude for the following places:
1. Kanyakumari ______ and________
2. Imphal _____________and________
3. Jaisalmer_________ and_________
4. Pune______________ and_________
5. Patna______________and________
A.
S.No. Location Latitude Longitude
1. Kanyakumari 8.08° N 77.570 E
2. Imphal 24.80° N 93.930 E
3. Jaisalmer. 26.01° N 69.30° E
4. Pune 18.32° N 73.51° E
5. Patna 25.61° N 85.13º E
2.Identify the words that match with Latitude and Longitude (parallel lines, vertical lines, horizontal lines)
A.
Latitudes: Parallel Lines, Horizontal lines.
Longitudes: Meridians, Vertical lines.
3. Look at the world map of time zones on the textbook.
a) if you travel from New Delhi to Paris which time zones are you moving to? ........
b) if you are travelling from Hyderabad to Tokyo which time zones are you moving to?
A.
a) -5.30 hours time zones.
b) +3.30 hours time zones.
4.Why is it difficult to study the formation of the Earth and its structure?
A.
1. There is no clear evidence regarding the origin of the Earth. So it is difficult to study the details regarding the formation of the Earth. The details on which what we rely now are just assumptions and possible theories.
2. There is some what an equal trouble regarding the internal structure of the Earth. The reason is that, we cannot go beyond a particular limit into the Earth.
3. The only way by which the interior is known to us is by the way the lava and other things from the interior, from under the mantle shoot up.
5.Read the paragraph under the heading “Internal structure of the earth” and answer the question.
*How can you say that the earth is still very active?
A.
1.The matter from deep inside the mantle shoots up through volcanoes and fissures on ocean floors and cools down to form the earth's crust.
2.In many areas on the earth, part of the earth's crust enters into the mantle and once again becomes molten.
3.This constant process of formation and destruction of the crust explains the fact that our earth is still very active.
4.The crust on which we live is still being changed by earthquakes, volcanoes, subdue tion of land and rise of mountains due to processes happening deep down the earth.
6.What is a grid and how does it help us?
A
The network of Latitudes and Longitudes is called Grid.
1.By which we can locate a place easily on a globe or map.
2.We can identify climate with the help of latitudes and local time by calculating longitudinal position.
7. Differentiate between:
a) Local and Standard time,
b) Equator and Prime Meridian.
A.
a) Differences between local and standard time:
8.If every state follows its local time then what problems would rise?
A.
1.If every state follows the local time, there will be a problem of understanding the real time or the local time or time of the town.
2.This causes confusion.
3.It could get our activities into trouble, especially related to the time of trains, flights, etc.
4.To avoid this confusion, every state follows its own standard time.
9.With the help of your teachers find out the standard meridian of the given countries.
i) Nepal. ii) Pakistan iii) Bangladesh
iv) England. v) Malaysia vi) Japan
A.
Standard Time Meridian of:
i) Nepal : 86° 20' East
ii) Pakistan : 74° 22' East
iii) Bangladesh: 90° 24' East
iv) England : 0° Greenwich
v) Malaysia : 105° East
vi) Japan : 135° East
10.Make a thought provoking poster on the Earth's protection.
A.
Choose the correct answers:
* 0 ° longitude is known as........... ( )
A) International Date Line
B) Equator
C) Tropics
D) Prime Meridian
* Outer layer of the earth is called ...( )
A) Crust
B) Mantle
C) Outer core
D) None of these
* The super (whole) continent is .... ( )
A ) Panthalsa
B ) Pangaea
C ) Tethys
D ) Laurasia
* Gold most prevalent in this layer.. ( )
A) Crust
B) Mantle
C) Outer core
D ) Inner core
* 0 ° latitude is known as............... ( )
A) International Date Line
B) Equator
C) Tropics
D) Prime Meridian
* The width of one time zone is ........ ( )
A) 10° of longitudes
B) 5° of longitudes
C) 15° of longitudes
D) 20° of longitudes.
* The network of latitudes and longitudes is ........ ( )
A) grid
B) atlas
C) map
D ) equator
*. ............. is the path of the earth around the sun ( )
A) The axis
B) The orbit
C) The tract
D) None of the above
* Alfred Wagener a geophysicist of .... ( )
A) Italy
B ) Austria
C) France
D) Germany
*. ............. is not an environmental crisis ( )
A) Global warming
B) Air pollution
C) Collision of asteroids
D ) The rise of water levels in oceans
* .............. are written like Vedanga Jyotisha, Surya Sidhanta and Bhagavata Purana ( )
A) Indians
B) Indo - Americans
C) Europeans
D ) Ancient Indians
* ..................is largest latitude ( )
A) North pole
B) Arctic circle
C) Equator
D) Tropic of cance
*Earth travels around the sun at a speed of .................. .... per hour ( )
A) 1,07,200 kms
B) 6,200 kms
C) 152 millions kms
D) 1,02,700 kms
* .......... is very thin layer of the earth ( )
A) Crust
B) Mantle
C) Outer core
D) Inner core
* Latitudes are............. ( )
A) circles
B) straight lines
C) semi - circles
D) curves
* ............. knew that the meridians passes through Ujjain ( )
A) Aryabhatta
B) Nagarjuna
C) Chanakya
D) Varahamihara
* ........................ is the thickest layer ( )
A) Outer core
B) Mantle
C) Crust
D) None of these
* ......... knew that the meridian go through Alexandria ( )
A) Aryabhatta
B) Chanakya
C) Varahamihara
D) Nagarjuna
* Longitudes are ......... ( )
A) circles
B) semi - circles
C) straight lines
D) curves
* ........... longitude is taken as Standard Meridian of India ( )
A) 83° 20' East
B) 82° 30' East
C) 83° 20' West
D) 82° 30' West
* ............ are useful to locate places on the earth ( )
A) latitudes
B) longitudes
C) grid
D) equator
* The universe started ......... years ago ( )
A) 18.7 billion years
B) 13.7 billion years
C) 16.7 billion years
D) 15.7 billion years
*. ....... Introduced continental drift theory ( )
A) Newton
B ) Darwin
C) Wagener
D ) Alexander
*Earth takes to complete one revolution ( )
A) 28 days
B) 30 days
D) 365 days
D) 366 days
* The Earth closest point from the Sun is........km ( )
A) 147 million km
B) 125 million km
B) 174 million km
D) 152 million km
* The radius of the earth is ........ ( )
A) 1,07,200 kms
B) 9000 kms
C) 8848 kms
D) 6000 kms
* ........... is the top most layer of the earth ( )
A ) Crust
B ) Core
C ) Mantle
D ) Centre
* Earth takes ..........to complete a rotation ( )
A) 365¼ days
B) 5 days
C) 1 days
D) 2 days
* Ancient Indians knew the latitude of a place by measuring the inclination of the polar star ( )
A) Dhruva
B) Arundhati
C) Polaris
D) None
* ................ is the biggest among all ( )
A) Galaxies
B) Milky way
C) Sun
D) Universe
* The world is divided into ... time zones ( )
A) 24
B) 44
C) 21
D) 12
* .......... layers consists of iron and nickel ( )
A) Crust
B) Mantle
C) Outer core
D) None of these
* The shape of the orbit is ......... ( )
A ) a circular path
B ) an elongated oval path
C ) a scaled oval path
D ) a triangular path
*. ........... of the following came into existence first ( )
A) Human beings
B) Plants
C) Animals
D) Ocean species
* ................ causes seasons on the earth ( )
A) Rotation of the Earth
B) Movement of the Moon around the Earth
C) Revolution of the earth.
D) Tilt of Earth's axis of rotation to its orbital plane
* ............... layers consists of silicons ( )
A) Outer core
B) Mantle
C) Crust
D) Inner core
*Earth's farthest point from Sun is .... km ( )
A) 152 million km
B) 147 million km
C) 149.5 million km
D) 150 million km
* The Earth began to form around ...... years ago ( )
A) 13.7 billion
B) 17.3 billion
C) 4 billion
D) 5 billion
