Case Study Questions Class 7 Geography Chapter 3 Our Changing Earth
CBSE Class 7 Case Study Questions Geography Our Changing Earth. Important Case Study Questions for Class 7 Board Exam Students. Here we have arranged some Important Case Base Questions for students who are searching for Paragraph Based Questions Our Changing Earth.
Case study 1
The lithosphere is broken into a number of plates known as the Lithospheric plates. You will be surprised to know that these plates move around very slowly – just a few millimetres each year. This is because of the movement of the molten magma inside the earth. The molten magma inside the earth moves in a circular manner. The movement of these plates causes changes on the surface of the earth. The earth movements are divided on the basis of the forces which cause them. The forces which act in the interior of the earth are called as Endogenic forces and the forces that work on the surface of the earth are called as Exogenic forces.
1.) What are lithospheric plates?
Answer- when The lithosphere is broken into a number of plates it is known as Lithospheric plates.
2.) Why do the lithospehric plates move very slowly?
Answer- because of the movement of the molten magma inside the earth.
3.) The earth’s movement is divided on what basis?
Answer- The earth movements are divided on the basis of the forces which cause them.
4.) What are endogenic forces?
Answer- The forces which act in the interior of the earth are called as Endogenic forces.
5.) Define exogenic forces.
Answer- the forces that work on the surface of the earth are called as Exogenic forces.
Case study 2
Endogenic forces sometimes produce sudden movements and at the other times produce slow movements. Sudden movements like earthquakes and volcanoes cause mass destruction over the surface of the earth.A volcano is a vent (opening) in the earth’s (1) through which molten material erupts suddenly. Similarly, when the Lithospheric plates move, the surface of the earth vibrates. The vibrations can travel all round the earth. These vibrations are called earthquakes . The place in the crust where the movement starts is called the focus. The place on the surface above the focus is called the epicentre. Vibrations travel outwards from the epicentre as waves.
1.) What are the effects of sudden movement of plates?
Answer- Sudden movements like earthquakes and volcanoes cause mass destruction over the surface of the earth.
2.) Volcano is a vent (opening) in the earth’s (1) through which molten material erupts suddenly. Name (1).
Answer- crust
3.) What happens to the surface of the earth when lithospheric plates move?
Answer- When the Lithospheric plates move, the surface of the earth vibrates.
4.) How are earthquakes caused?
Answer- when the Lithospheric plates move, the surface of the earth vibrates. The vibrations can travel all round the earth. These vibrations are called earthquakes.
5.) What is the places on the surface called?
Answer- epicentre
Case study 3
The landscape is being continuously worn away by two processes – weathering and erosion. Weathering is the breaking up of the rocks on the earth’s surface. Erosion is the wearing away of the landscape by different agents like water, wind and ice. The eroded material is carried away or transported by water, wind, etc. and eventually deposited. This process of erosion and deposition create different landforms on the surface of the earth.
1.) Name the two processes by which landscape is completely worn away?
Answer- weathering and erosion
2.) Define weathering.
Answer- Weathering is the breaking up of the rocks on the earth’s surface.
3.) Give a brief description about how erosion is caused?
Answer- Erosion is the wearing away of the landscape by different agents like water, wind and ice. The eroded material is carried away or transported by water, wind, etc.and eventually deposited.
4.) What happens to the surface of earth through the process of erosion and deposition?
Answer- process of erosion and deposition create different landforms on the surface of the earth.
Case study 4
As the river enters the plain it twists and turns forming large bends known as meanders. Due to continuous erosion and deposition along the sides of the meander, the ends of the meander loop come closer and closer. In due course of time the meander loop cuts off from the river and forms a cut-off lake, also called an ox-bow lake. At times the river overflows its banks. This leads to the flooding of the neighbouring areas. As it floods, it deposits layers of fine soil and other material called sediments along its banks. This leads to the formation of a flat fertile floodplain. The raised banks are called levees.As the river approaches the sea, the speed of the flowing water decreases and theriver begins to break up into a number of streams called distributaries.
1.) What are the large bends in the plain known as ?
Answer- meander
2.) How are ox-bow lakes formed?
Answer- Due to continuous erosion and deposition along the sides of the meander, the ends of the meander loop come closer and closer. In due course of time the meander loop cuts off from the river and forms a cut-off lake, also called an ox-bow lake.
3.) How are sediments formed around the banks of river?
Answer- At times the river overflows its banks. This leads to the flooding of the neighbouring areas. As it floods, it deposits layers of fine soil and other material called sediments along its banks.
- What are levees?
Answer- the raised banks are called levees.
5.) What are distributaries?
Answer- As the river approaches the sea, the speed of the flowing water decreases and theriver begins to break up into a number of streams called distributaries.
Case study 5
The erosion and deposition of the sea waves gives rise to coastal landforms. Seawaves continuously strike at the rocks. Cracks develop. Over time they become larger and wider. Thus, hollow like caves are formed on the rocks. They are called sea caves. As these cavities become bigger and bigger only the roof of the caves remain, thus forming sea arches. Further, erosion breaks the roof and only walls are left. These wall like features are called stacks. The steep rocky coast rising almost vertically above sea water is called sea cliff.
1.) Which two activities give rise to coastal landforms?
Answer- The erosion and deposition of the sea waves gives rise to coastal landforms.
2.) How are sea caves formed?
Answer- due to continuous striking of sea waves at rocks, cracks develop in the rocks which with time become larger and wider. This form hollow like cave on the rocks known as sea caves.
3.) What are sea arches?
Answer- when the cavities in the rocks become bigger and bigger only the roof of the caves remain,they form sea arches.
4.) When erosion breaks the roof and only walls are left.what are these walls known as?
Answer- These wall like features are called stacks.
5.) Define sea cliff?
Answer- The steep rocky coast rising almost vertically above sea water is called sea cliff.
Case study 6
An active agent of erosion and deposition in the deserts is wind. In deserts you can see rocks in the shape of a mushroom, commonly called mushroom rocks. Winds erode the lower section of the rock more than the upper part. Therefore, such rocks have narrower base and wider top. When the wind blows, it lifts and transports sand from one place to another. When it stops blowing the sand falls and gets deposited in low hill – like structures. These are called sand dunes. When the grains of sand are very fine and light, the wind can carry it over very long distances. When such sand is deposited in large areas, it is called loess.
1.) Name an active agent of erosion and deposition in the deserts?
Answer- wind
2.) What are rocks in the shape of mushroom found in deserts known as?
Answer- mushroom rocks
3.) Why do mushroom rocks have narrower base and wider top?
Answer- Because winds erode the lower section of the rock more than the upper part.
4.) What are sand dunes? How are they formed?
Answer- when the wind blows, it lifts and transports sand from one place to another. When it stops blowing the sand falls and gets deposited in low hill – like structures. These are called sand dunes.
5.) What is loess?
Answer- When the grains of sand are very fine and light, the wind can carry it over very long distances. When such sand is deposited in large areas, it is called loess.
Also See: Previous Chapter Case Based Questions