Table of Contents
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.
Section 3: Our Changing Earth
For NCERT Solutions for 7th Class for different subjects, students can visit the connected article.
NCERT Solutions for 7th Class Social science 3rd Chapter – Our Changing Earth – Download PDF
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.
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
- Match the following.
| (i) Glacier | (a) Seashore |
| (ii) Meanders | (b) Mushroom rock |
| (iii) Beach | (c) River of ice |
| (iv) Sand dunes | (d) Rivers |
| (v) Waterfall | (e) Vibrations of earth |
| (vi) Earthquake | (f) Seacliff |
| (g) Hard bedrock | |
| (h) Deserts |
Answer:
| (i) Glacier | (c) River of ice |
| (ii) Meanders | (d) Rivers |
| (iii) Beach | (a) Seashore |
| (iv) Sand dunes | (h) Deserts |
| (v) Waterfall | (g) Hard bedrock |
| (vi) Earthquake | (e) Vibrations of earth |
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:
- The changing Environment on Earth and its Effects
- Contextual investigation on Earthquake
- Significant Land Forms
- Work of River
- Work of Sea Waves
- Work of Ice
- 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.
FAQs on NCERT Solutions for 7th Class Social Science Geography 3rd Chapter
1. List out the topics covered in Chapter 3 of NCERT Solutions for 7th Class Social Science Geography?
The topics that are canvassed in the 3rd Chapter of NCERT Solutions for 7th Class Social Science Geography are –
- The changing Environment on Earth and its Effects
- Contextual analysis on Earthquake
- Major Landforms
- Work of River
- Work of Sea Waves
- Work of Ice
- Work of Wind
2. How might students score excellent grades in tests involving the NCERT Solutions for 7th Class Social Science Geography 3rd Chapter?
Before launching with test arrangements, students really should be aware of the total prospectus first. Afterward, a strong report plan designating time for every one of the subjects must be made. The NCERT Solutions at INFINITY LEARN give replies to every one of the reading material inquiries to hone the applied information and critical thinking abilities of students. Every one of the arrangements PDF can be gotten to involving the download choice for nothing with no time limitations.
3. What are sand dunes explained in Chapter 3 of NCERT Solutions for 7th Class Social Science Geography?
At the point when the breeze blows, it lifts and transports sand starting with one spot then onto the next. At the point when the breeze quits blowing, the sand falls and gets saved in the low slope-like constructions. These are called sand rises. They are generally found in desert regions. To get more familiar with the principle points and accomplish a solid hold over them, students ought to allude to the NCERT Solutions made by individual informed authorities at INFINITY LEARN.
