NCERT Solutions for Class 7 Social Science Geography Chapter 3 Our Changing Earth

NCERT Solutions for Class 7 Social Science Geography Chapter 3 – Our Changing Earth help students learn how the surface of the Earth keeps changing all the time. This chapter explains that the movements of the Earth are caused by two types of forces – endogenic forces (from inside the Earth) and exogenic forces (from outside the Earth). Natural events like earthquakes and volcanoes are caused by endogenic forces and often lead to mass destruction. 

On the other hand, slow processes like weathering and erosion continuously wear away the landscape. The Class 7 Geography Chapter 3 Questions and Answers cover all the important concepts in an easy way. These NCERT Solutions are prepared by experts to match the latest CBSE Class 7 Social Science syllabus. You can also download the FREE PDF of Our Changing Earth Class 7 to study anytime and clear your basics.

NCERT Book Solutions 7th Class Social Science Geography 3rd Chapter

The movements of Earth are isolated based on the powers, which cause them. The powers, which act inside of the Earth are called Endogenic powers and the powers that work on the outer layer of the Earth are called Exogenic powers. Quakes and Volcanoes cause mass annihilation over the outer layer of the Earth. 

The scene is in effect ceaselessly eroded by two cycles – enduring and disintegration. These NCERT Solutions for 7th Class Social Science Geography give students answers for every one of the inquiries spread out in the NCERT 7th Class Social Science Geography coursebook.

NCERT Solutions for 7th Class Social science 3rd Chapter – Our Changing Earth – Download PDF

The NCERT Solutions for 7th Class Social Science Chapter 3 – Our Changing Earth help students understand how natural forces like earthquakes, volcanoes, and rivers shape the Earth's surface. These easy-to-follow answers explain tough topics in simple words, making learning fun and clear. 

Students can use these NCERT Solutions to prepare better for exams and complete homework quickly. You can also download the PDF for all chapters for free and study anytime, anywhere. It’s a smart way to boost your knowledge and score well in Social Science. Simply Click link to download PDF.

NCERT Solutions for Class 7 Social Science Geography Chapter 3 TEXTUAL QUESTIONS

Ques 1. Why do the plates move?

Ans. The Lithospheric plates move around because of the movement of the molten magma inside the Earth.

Ques 2. What are exogenic and endogenic forces?

Ans. Earth’s movements are divided on the basis of the forces which cause them. The ones that work on the Earth’s surface are called exogenic forces while the ones that works in the Earth’s interior are called endogenic forces. The erosional and depositional activities of wind and water are examples of exogenic forces. Earthquakes and volcanoes are examples of endogenic forces.

Ques 3. What is erosion?

Ans. Erosion is the weathering or wearing away of the landscape by different agents like wind, water, and ice.

Ques 4. How are flood plains formed?

Ans. During its course through a plain, a river sometimes over flows its banks. This leads to the flooding of the neighbouring areas. As it floods, the river water deposits layers of fine soil and sediments on its banks. This leads to the formation of a flat, fertile flood plain.

Ques 5. What are sand dunes?

Ans. In deserts, when the wind blows, it lifts and transports sand from one place to another. When it stops blowing, the sand particles fall and get deposited in low hill-like structures called sand dunes.

Ques 6. How are beaches formed?

Ans. The erosional and depositional activities of the sea waves give rise to different coastal landforms. A beach is one such coastal landform. It is formed when the sea waves deposit sediments along the seashore.

Ques 7. What are ox-bow lakes?

Ans. An ox-bow lake is a crescent-shaped lake formed by a meandering river. During its journey through a plain, a river twists and turns to form meanders. Erosion and deposition occur constantly along the sides of a meander, thereby causing the ends of its loop to come closer and closer. In due course of time, the meander loop cuts off from the river and forms a cut-off, crescent-shaped ox-bow lake.

Also Check: NCERT Solutions for Class 7 Social Science Civics | NCERT Solutions for Class 7 Social Science History

Tick the correct answer

(i) Which is not an erosional feature of sea waves?

(a) Cliff

(b) Beach

(c) Sea cave

Answer: b

(ii) The depositional feature of a glacier is:

(a) Flood plain

(b) Beach

(c) Moraine

Answer: c

(iii) Which is caused by the sudden movements of the earth?

(a) Volcano

(b) Folding

(c) Flood plain

Answer: a

(iv) Mushroom rocks are found in:

(a) Deserts

(b) River valleys

(c) Glaciers

Answer: a

(v) Oxbow lakes are found in:

(a) Glaciers

(b) River valleys

(c) Deserts

Answer: b

3. Match the following.

Answer:

NCERT Solutions for Class 7 Social Science Geography Chapter 3 - Give Reasons

Some rocks have the shape of mushrooms.

As we know that wind in deserts is an active agent of erosion and deposition. Winds erode the lower section of the rock more than the upper section. So, such rocks have a narrower base and wider top, which gives them a mushroom-like appearance. Hence, some rocks in deserts have mushroom-like shapes.

Flood plains are very fertile.

Flood deposits layers of fine soil and other materials called sediments along its banks. This leads to the formation of fl at fertile flood plain. Hence, these flood plains have fertile soil.

Sea caves are turned into stacks.

As the sea caves’ cavities become bigger and bigger only the roof of the caves remain, thus forming sea arches. Again, erosion even breaks the roof and only walls are left. These wall-like features are called stacks. In this way, sea caves change into stacks.

Buildings collapse due to earthquakes.

i) Earthquakes are the sudden vibrations caused within the Earth’s surface as a result of the movement of the Lithospheric plates.

ii) Such vibrations, when they are of high intensity, cause damage to the things on the Earth’s

iii) Various human-made (e.g., buildings) and natural (e.g., trees) constructions can break down and collapse under the effect of the vibrations because they are situated on the Earth’s surface.

Our Changing Earth Summary

This part from the NCERT Social Science Geography book gives definite data about:

1. The changing Environment on Earth and its Effects
2. Contextual investigation on Earthquake
3. Significant Land Forms
4. Work of River
5. Work of Sea Waves
6. Work of Ice
7. Work of Wind

Our Environment is the NCERT Social Science Geography book for students in Class 7. For NCERT Solutions for 7th Class Social Science, visit the connected article.

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