I. KEY WORDS:
1. Plate tectonics: The region where the two plates meet and push each other, One plate is pushed under the mantle while the other plate is pushed up to form a chain of mountains. This movement of plates is called ‘plate tectonics’.
2. Igneous rocks: while the molten materials cool and form hard rocks called ‘Igneous rocks’.
3. Sedimentary rocks: The debris is transported by rivers to the sea where layer after layer is accumulated in the bottom and overtime get transformed into sedimentary rocks.
4. Loess plains: In the deserts plains formed by the deposition of loess are called Loess Plains.
5. ‘U’ shaped valley: Glaciers create a U shaped valley through the dual process of plucking and abrasion.
II. SHORT ANSWERS:
1. Name the natural realms of the Earth.
A.
Scientists usually talk of four natural realms on the Earth. These are
1. Lithosphere,
2. Hydrosphere,
3. Atmosphere and
4. Biosphere
2. What is called lithosphere?
A.
The solid crust or the hard top part of the Earth
made up of rocks and minerals and covered with a thick layer of soil.
3. Name the major plates on the Earth.
A.
There are about seven major plates on the Earth
They are
1. African,
2. North American,
3. South American,
4. Indo Australian,
5. Antarctic,
6. Eurasian and
7. Pacific Plates.
4. What are called second order of landforms?
A
1. These are result of the internal processes of the earth.
2. These landforms like mountains, plains and plateaus are called ‘Second Order landforms’.
5. What are called third order of landforms? how they are formed?
A.
1.The landforms shaping by wind and water are called third order of landforms.
2.They are carved mountains, valleys, deltas and sand dunes.
3.They are formed by the processes like weathering, erosion, transportation and deposition.
6.How is seafloor spreading?
A.
1.Geologists studying the crust under the sea have mid ocean ridges or ranges.
2.They are formed by the lava rising up from the mantle.
3.The eruptions on the ridge create new ocean floor made of basalt rocks newest
crust formed on the planet.
4.This fresh crust is being slowly pulled away from the ridge widening the ocean basin.
5.This leads to what is called ‘sea-floor spreading’.
7.What are called Volcanoes?
A.
1.Volcanoes are places on the earth’s surface where molten material from the mantle erupts.
2.This molten material is also accompanied by steam, smoke and various forms of gases from the depths of the earth.
8. Name some important volcanoes in the world.
A.
1.Stromboli - Sicily
2.Mt Pelee - West Indies
3.Mount Vesuvius - Italy
4.Fujiyama - Japan
5.Cotopaxi - Equador
6.Mayon - Philippines
7.Barren, Narcondam - India
8.Kilimanjaro - Tanzania.
9.What are called 'intrusive landforms'?
A.
1.During the time of volcanic eruption the lava may not reach the surface.
2.It may cool under the surface and become rocks.
3.These are called ‘intrusive landforms’.
10.What are called ‘extrusive landforms’?
A.
A part of the lava which pours on the surface of the earth forms the ‘Extrusive landforms’.
11.What is the importance of Pacific ring of Fire?
A.
1.Geologists noted that high number of earthquakes and volcanic activity occurring around the ‘Pacific Rim’.
2.About ¾ of all active volcanoes in the world lie within the Pacific Rim.
3.It is along Pacific plate boundaries that many volcanoes and earthquakes occur, giving it the name ‘The Pacific Ring of Fire.’
12. What are called third order of landforms?
A.
1.Shaping the landforms by wind and water is called ‘Third Order Landforms’.
2.These land forms include features like carved mountains, valleys, deltas, sand dunes etc.
13. What do mean weathering?
A.
1.Weathering is a process by which the gradual disintegration of rocks by atmospheric forces or weather forces.
2.The rocks, when exposed to heat expand and contract when they cool down.
3.Due to this, it gradually becomes brittle and begins to break down.
4.Water and moisture in the air reacts with the chemicals of the rocks and further weakens the rock.
5.These processes by which the rocks are weakened and broken are called ‘weathering’.
14. What are called mushroom rock?
A.
The lower section of the rocks erode by winds more than the upper part. Such rocks have narrow at bottom and wider on the top like mushrooms. So they are called mushroom rocks.
15. What is a canyon?
A.
1) A canyon is characterized by steep slopes and may deep as a gorge
2) A canyon is wider at its top than the bottom.
16. What are the advantages of volcanic eruption?
A.
1. Fertile soils are formed like Deccan plateau.
2. Valuable minerals from interior of the earth were brought to the surface.
17. List out the landforms originated due to the work of waves?
A.
1. The erosion and deposition by the sea waves give rise to coastal landforms.
2. Sea caves, Sea arches, Sea stack, Sea Cliff, beaches are formed due to the work of waves.
18. List out the landforms originated due to work of winds.
A.
1. The wind action creates a number of interesting erosional and depositional features in the desert.
2. Mushroom Rock, Inselberg, Sand Dunes, Loess Plains are formed due to work of winds.
18. How is loess plain are formed?
A.
1. The fine dust blown beyond the desert limit is deposited on neighbouring lands.
2. It is yellow in colour and is very fertile. This soil is called ‘Loess' with fine loam, rich in lime and extremely porous.
3. The plains formed by the deposition of loess are called Loess Plains.
19. What are called plates? how many plates are there on the earth?
A.
1. Plates are the massive base of Rock on which all the continents and the oceans are actually situated.
2. There are 6 major and several minor plates on the earth.
3. The African, North American, South American, Indo Australian, Antarctic, Eurasian and Pacific are the major plates.
4. Nazce and Arabian are the minor plates.
III. IMPROVE YOUR LEARNING:
1. Find the odd one out in the context of lithosphere and give reasons for your choice Byson gorge; Grand Canyon; Ozone; Thar desert.
A.
Out of these ozone is the odd one .
Reasons :
1. Byson gorge and Grand canyon are formed by rivers.
2. Thar desert is a vast sand desert, with scanty water.
3. Above three are landforms.
4. But Ozone is an inorganic molecule with the chemical formula and layer of Atmosphere.
2. How is the lithosphere formed?
A.
1. Lithosphere is the solid crust or the hard top part of the Earth.
2. The Earth began as a ball of swirling dust and clouds and passed through a molten stage.
3. The Earth was so hot that it was molten.
4. While the earth was boiling in a liquid form, the heavier particles went to the bottom and formed the mantle and core.
5. The lighter particles cooled at the top and formed the top layer i.e., the crust of the Earth.
6. In such a way the crust or lithosphere was formed.
3. How are the continental plates formed and how are they eventually destroyed ?
A.
1. Geologists said that all the continents and even the oceans are actually situated on massive base of rocks called plates.
2. These plates actually float on the mantle.
3. They are constantly being pushed each other and therefore keep moving slowly.
4. One plate is pushed under into the mantle while the other plate is pushed up to form a chain of mountains.
5. The incoming plate dips under the stable plate and goes into the mantle of the earth and becomes molten due to the heat of the mantle.
6. Thus the continental plates are eventually destroyed.
4. List out the landforms formed due to the river work.
A.
Many landforms are formed due to the work of the river .They are
1. V - shaped valley: The flow of a river with great force cutting the mountain vertically. As a result V - shaped Valleys formed.
2. Gorge: Where the rocks are very hard , the river cuts a narrow valley with steep sides called Gorges
3. Canyon: A deep valley with steep like slopes and is wider at its top than at the bottom is called a canyon .
4. A plunge pool: The water falls with great force and dig out the rock beneath to form a plunge pool.
5. Plain: When the river is in floods it cuts the soil and when it is not in flood it deposits silt and thus forms vast flood plains .
6. Meanders: The river constantly changes its course and cuts new path and forms gentle snake like meanders.
7. Ox - bow lakes: Due to the deposition along the ends of the meander loop comes closer. The meander loop cuts off from the river and forms a cut off lake which is called ox - bow lake.
8. Delta: When a river reaches the sea, the fine material is deposited at its mouth forming a delta(Δ).
5. Draw a table as given below and fill information. And write a small paragraph to explain the similarities and differences that you can think of in the context of earth’s external changes. (if there is no information available in the text, leave the columns blank)
A.
Wind:
1. Wind takes many forms and carries away the surface of the land in the higher places
Water:
1. Water reacts with the chemicals of the rocks and further weakens the rock .
2. Water acts as moving agent of the earth.
Glacier:
1. The ice on these glaciers melt throughout the year and flows to low areas as rivers and streams.
2. They also erode, transport and deposit rock materials.
6. Why are Glaciers not found in your surroundings ?
A.
1. Glaciers are mostly found either in mountainous areas or the polar regions.
2. We are in the state of Telangana. It is a semi - arid area and has a predominantly hot and dry climate.
3. Summers start in March, and peak in May with average high temperatures in the 42° C range.
4. A dry, mild winter starts in late November and lasts until early February with little humidity.
5. Average temperatures of the state 22°C -23°C range.
6. In such hot and dry conditions glaciers are not formed.
7. How are Beaches formed and name some Beaches.
A.
Beaches form as waves deposit sand and other sediment on the shore.
Names of some beaches:
1) Diu Beach.
2) Manori Beach, Mumbai.
3) Versova Beach, Mumbai.
4) Mivamar Beach, Panaji.
5) Karwar Beach, Karnataka.
6) Fort Kochi, Cochin.
7) Kovalam Beach, Trivandrum.
8) Marina Beach, Chennai.
9) RK Beach, Visakhapatnam.
10) Chandipur Beach, Odisha.
8. How is the human lifestyle responsible for extension of deserts?
A.
1. Desertification is a social problem involving people at all stages as a cause and as victims.
2. The anthropogenic (human) causes of desertification are over cultivation, over grazing, deforestation and poor irrigation practices.
3. These factors Increase in temperature leads to drying out of water and it further causes expansion of deserts.
4. Mismanagementt of dry land ecosystems by humans can cause desertification.
5. Overgrazing is also significant factors for the expansion of deserts.
6. Thus activities of human beings lead to the extension of deserts.
9. Find out the order of the landforms for the following:
A.
1. The Himalayan - 2nd order Landform
2. The Pacific Ocean. - 1st order Landform
3 . Asia Continent - 1st order Landform
4 . Byson Gorge - 3rd order Landform
5. Jog waterfall - 3rd order Landform
6. Rocky mountains - 2nd order Landform
7. The Indian Ocean - 1st order Landform
8. The great rift valley - 3rd order Landform
10. Draw the map of world plates by observing map 2.
A.
11. Read the para under the title 'Erosion' on page 20 and comment on it.
Erosion: Flowing water and wind have great power and can slowly wear away or cut away the rocks and soil cover in higher places. Water acts in many ways, as rain, river, flowing ground water, sea waves, glaciers. etc. Wind too takes many forms like storms, gusts, steady winds etc. The active wearing away of the earth's surface by these moving agents is called erosion.
A.
1. Erosion is the process by which soil and rock are removed from the earth's surface by exogenic processes such as wind or water flow, and then transported and deposited on their locations while erosion is a natural process.
2. Human activities have increased by 10 - 40 times the rate of which erosion is occuring globally.
IV. CHOOSE THE CORRECT ANSWERS:
* Mushroom rock is the erosional form of rock caused by ....... ( )
A) winds
B) waves
C) rivers
D ) glaciers
* Landforms formed due to wind and water are called .......( )
A) 1st order
B) 2nd order
C) 3rd order
D) 4th order
* Identify the odd one ( )
A) Stack
B) Mushroom rock
C) Inselberg
D) Loess plain
* Angel waterfalls is on the river ( )
A) River Churun
B) Colarado River
C) River Ganga
D) River Nile
* ............. is thehe highest waterfall in India.( )
A) Kunchikal falls
B) Tugela fall
C) Niagara falls
D) none
* ....... ..... is called the biosphere ( )
A) air
B) life
C) rocks
D) water
*............... Mountains were formed by the process of the Indian plate pushing into the Eurasian plate ( )
A) The Rockie mountains
B) The Andes mountains
C) the Himalayas.
D) The Aravali hills
*Nazca plate is located in ............ ( )
A) Atlantic ocean
B) Pacific ocean
C) Indian ocean
D) Southern ocean.
*A head land cutting out into the sea is ( )
A) Bay
B) Cape
C) Sea Arch
D) Sea Cliff
* The Grand Canyon is on ............ river ( )
A) Ganga
B) Colarado
C) Amazon
D) Nile
* V - shaped valleys are formed by ( )
A) rivers
B) glaciers
C) winds
D) waves
* The gentle turns of the river are called as .. ( )
A) The glaciers
B) The meanders
C) The waterfalls
D) Lake
* ............. are suitable for construction of
dams.( )
A) Gorges
B) meanders
C) waterfalls
D) Canyon
* The highest waterfall in the world is ( )
A) Angel falls
D) Tugela
B) Jog falls
D) none
* .............. is comes under Eurasian plate ( )
A) Europe & Asia
B) Europe & Africa
C) North America
D) South America
*The solid crust or the hard top part of the Earth is called ............ ( )
A) Biosphere
B) Atmosphere
C) Lithosphere
D) Hydrosphere
*........ are suitable for construction of dams ( )
A) Canyons
B) Waterfalls
C) Gorges
D) Plunge pools
* Higher number of earthquakes and volcanic activity occur in centrally around the. ( )
A) the Indian Ocean basin
B) the Atlantic ocean basin
C) the Pacific Ocean basin
D) the Arctic Ocean basin
* ........... is the second highest waterfall in the
world ( )
A) Tugela falls
B) Kunchikal
C) Niagara falls
D) none
*The meander loop cuts off from the river and forms ( )
A) Ox - bow lake
B) V- shapped valley
C) U- shapped valley
D) Delta
* Sand dunes are formed by the action of ( )
A) glaciers
B) winds
C) waves
D) rivers
* ................ is the smallest plate ( )
A) Eurasian
B) Pacific
C) Arabian
D) Indo - Australian
* Oceans and continents are ............ ( )
A) second order landforms
B) third order landforms
C) first order landforms
D) fourth order landforms
* A glacier erodes through a process called ( )
A) Erosion
B) Abrasion
C) Weathering
D) Plucking
* ............ is highest waterfall in the world ( )
A) The Angel fall
B) The Niagara
C) The Jog waterfall
D) The Elephanta
* .............. is not the part of denudation ( )
A) Weathering
B) Erosion
C) Plucking
D) Deposition
* The mount vesuvius is in the.......( )
A) Japan
B) Italy
B) Philippines
D) Tanzania
* unstable hills of sand are called ( )
A) The sand dunes
B) Loess
C) Inselberg
D) Mushroom rocks
* Slow maving of mass of ice is called as ( )
A) The glacier
B) The river
C) The waterfall
D) The meander
* ................ example of fold mountains ( )
A) Cacasus
B) Ural
C) Himalayas
D) None
*A wide mouthed recess in the line of the coast is ( )
A) Sea Arch
B) Sea Cliff
C) Bay
D) Cape
* ........... is the light house of The Mediterranean sea ( )
A) Cotopaxi
B) Stromboli
D) Kilimanjaro
D) Fujiyama
* ........... second highest waterfall. ( )
A) The Jog fall
B) The Tugela fall
C) The Angel fall
D) The Nayagara
* U - shaped valleys are formed by ( )
A) glaciers
B) rivers
C) winds
D) waves
* Mountains, plains and plateaus are called ( )
A) 1st order landforms
B) 2nd order landforms
C) 4th order landforms
D) 3rd order landforms
* About ............... of the world's land is made up of deserts.( )
A) ⅕th
B) ¼th
C) ⅙th
D) ⅒th
* ............is highest waterfall in India ( )
A) The Jog fall
B) The Tugela fall
C) The Angel fall
D) The Nayagara fall
* ............... is the largest delta in the world ( )
A) the Krishna delta
B) the Godavari delta
C) the Indus delta
D) the Sunderbans
* Identify the odd one ( )
A) Sea cliff
B) Stack
C) Inselberg
D) Sea Arch
