DELHI PUBLIC SCHOOL TAPIVII LEARNING PARTNERSHIP Geogrpahy CW 3

Answer key

1. Brain Storming Task: Brainstorm on the past ‘Earthquakes that occurred in India’.

[Time: 10 min MI: Verbal, Intrapersonal, Interpersonal RBT: Analysis]

Read and Understand Task 1: Read the lesson ‘Inside Our Changing Earth’,so as to acquire knowledge with understanding.

Earth Movement Evolution of Landforms The figure 2.4 Rock Cycle, focussing on Magma the eruption of volcano How the Earthquakes occurs Earthquake hit regions Earthquake prepare

Now share each other's ideas and come down to three important points discussed in yourgroups. Write down the points and share it with the larger group. Give feedback to each other.

[Time: 1 hr MI: Verbal, Intrapersonal, Interpersonal RBT:Analysis]

1. Understanding and Note making Task: View the clip and discuss on the understanding of the concept and make notes.Visual image: Landforms

[Time: 30 min MI: Verbal; Logical; Intrapersonal RBT: Analysis]

2. Read and Understand Task 2 : Read the lesson following topics,so as to acquire knowledge withunderstanding.

Endogenic or Endogenic Forces: The term Endogenic means internal processes and phenomena that occur beneath the surface

of the earth or any other celestial body.

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Earthquake and volcanic eruption: Visualize the image and brainstorm on the image displayed. Understand and make notes on the topic Evolution of landforms.

Exchange ideas based on Earthquake and earthquake hit regions. Correlate your ideas to the brainstorming task done previously.

Earthquake Eruption

[Time: 50 minutes MI: Verbal, Logical RBT: Understanding]

3. Writing Task 1: Read Lesson 3, and discuss the following:Q1 Explain the following terms: (2 marks)

[Lithospheric plates, Endogenic forces, Exogenic forces, earthquakes, volcanoes, focus, Epicentre, weathering, erosion, meanders]

[Time:30 minutes MI: Verbal, Logical; IntrapersonalRBT: Understanding]

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4. Read and Understand Task 3 : Read the lesson ‘Earthquake- A case study’,so as to acquire knowledge with understanding. Visualize and analyse the images and understand about the images. Explain earthquake, focus and epicentre. Work of a River, Sea waves, Ice, wind

[Time: 50 minutes MI: Verbal, Logical RBT: Understanding]

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5. Writing Task 2: Read the lesson 3, discuss and write the following questions:

1.Name the two types of tectonic movement.

Ans: Vertical earth movement and horizontal earth movement are the two kinds of tectonic movement.

2.What are volcanoes?

Ans: A volcano is an opening in the earth’s crust which allows hot molten rock, ash and gases to escape from below the surface.

Where are the volcanoes found?Ans:

Volcanoes are generally found where tectonic plates are pulled apart or come together. Volcanoes can also form where there is stretching and thinning of earth’s crust, such as in the (African) rift valley.

3.How a water fall formed?

Ans:The running water in the river erodes the landscape. When the river tumbles at steep angle over very hard rocks or down a steep valley side it forms a waterfall.

4.What do you mean by mushroom rocks?Ans: An active agent of erosion and deposition in the deserts is wind. In desert we can see rocks in the shape of mushroom, commonly called mushroom rocks. The wind erodes the lower section of the rock more than the upper part.

5.Define Loess.Ans:When the grains of sand are very fine and light, the wind can carry it over very long distance. When such sand is deposited in large areas, it is termed as loess.

6.What is a delta?Ans:The river becomes so slow that it begins to deposit its load. Each distributary forms its own mouth. The collection of sediments from all the mouth forms a delta.

[Time: 30 minutes MI: Verbal; Logical; Intrapersonal RBT: Understanding]

6.Writing Task: Complete textual exercise given on page 17 Ncert Geography unit-3

Q. 1. Answer the following questions briefly:(i)  Why do the plated move?(ii)  What are exogenic and endogenic force?(iii) What is erosion?(iv) How are flood plains formed?(v) What are sand dunes?

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(vi) How are beaches formed?(vii) What are ox-bow lakes?Ans. (i) The plates move because of the movement of the molten magma inside the earth.(ii) Exogenic forces. The forces that work on the surface of the earth are called as exogenic forces.Endogenic forces. The froces that act in the interior of the earth are called as endogenic forces.(iii) Erosion is the wearing away of the landscape by different agents like water, wind and ice.(iv) During floods, layers of fine soil and other material called sediments are deposited on the river bank. This leads to the formation of a flat fertile flood plains.(v)Sand dunes are low hill-like structures formed by the deposition of sand in the deserts.(vi) Beaches are formed when the sea waves deposit sediments along the shores of the sea.(vii) When the meander loop is cut off from the main river, it forms a cut-off lake. As its shape is like an ox bow, it is also known as ox-bow lake.Q. 2. Tick the correct answer:(i)  Which is not an erosional feature of sea waves?(a) Cliff (b) Beach (c) Sea cave.(ii) The depositional feature of a glacier is(a) Flood plain (b) Beach (c) Moraine.(iii) Which is caused by the sudden movements of the Earth ?(a) Volcano (b) Folding (c) Flood plain.(iv) Mushroom rocks are found In(a) Deserts (b) River valleys (c) Glaciers.(v) Ox bow lakes are found In(a) Glaciers (b) River valleys (c) Deserts.Ans. (i) – (a), (ii) – (c), (iii)-(a) , (iv) -(a), (v)-(b)

Q. 4. Give reasons:(i) Some rocks have a shape of a mushroom.(ii) Flood plains are very fertile.(iii) Sea caves are turned into stacks.(iv) Buddings collapse due to earthquakes.Ans. (i) In deserts, winds usually erode the lower section of the rock more than the upper part. Therefore, such rocks have narrower base and wider top, which take the shape of a mushroom.

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(ii) Flood plains are formed by the deposition of fine soil and other material called sediments on the river banks. As the soil and sediments are brought by flood water, they are very fertile.(iii) Sea waves strike at the rocks. As a result cracks develop which become bigger over time and hollow like caves are formed on the rocks. They are called sea caves. These cavities become bigger and bigger and a time comes when only the roof of the caves remain to form sea arches. Further erosion breaks the roof and only walls are left. These wall like features are called stacks. In this way, sea caves are turned into stacks.(iv) Most of the buildings are not safe enough to resist the vibrations of the earthquakes. They are not made earthquake-proof. They collapse tearing apart due to shallow foundation and lack of adequate steel in the interior design.Q. 5. ActivityObserve the photographs given below. These are various features made by a river. Identify them and also tell whether they are erosional or depositional or landforms formed by both.Q-5 Activity (Do it in your Textbook only)

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