SEBA Class 7 Social Science (English Medium) Chapter 3 – The Earth’s Surface and Its Changes Solutions & Summary
Get detailed solutions for SEBA Class 7 Social Science Chapter 3 – “The Earth’s Surface and Its Changes“, designed for English medium students. This chapter explores the dynamic nature of the Earth’s surface, highlighting the natural forces and human activities that contribute to its continuous transformation. It covers key topics such as weathering, erosion, deposition, and plate tectonics, explaining how these processes shape landforms like mountains, valleys, rivers, and plains.
Students will learn about the role of wind, water, glaciers, and earthquakes in modifying the Earth’s surface. The chapter also discusses how human actions like deforestation, mining, and urbanization impact geographical changes. Understanding these concepts is crucial for appreciating the Earth’s evolving landscape and for taking steps toward environmental conservation.
Our solutions include NCERT-based textbook answers, multiple-choice questions (MCQs), and a chapter summary, providing students with in-depth explanations to enhance their understanding and exam performance.
Class 7 Social Science (English Medium) PDF Solutions 2025-26 | SCERT Assam
Class 7 Social Science
Chapter – 3 Ospin Academy
The Earth’s Surface and its Change
Exercise:
1. Write answers to the following (within 30 words)
(i) What do you mean by atmosphere?
Ans: The blanket of air surrounding the surface of our earth is called the atmosphere. All living beings inhabiting the earth depend on this atmosphere.
(ii) What is the yearly movement of plates?
Ans: An average rate of about 1.5 centimeters (0.6 inches) a year.
(iii) Write about temporary wind?
Ans: Temporary wind also known as gusts or sudden bursts of air can have a significant impact on our environment and daily activities.
(iv) What is sand dune?
Ans: When the wind blows, it carries and transports the sands from one place to another. In some areas when the velocity of wind decreases, the blown away sand gets deposited forming low hill like structure. These are called “sand dunes’.
(v) What is an Ox – bow lake?
Ans: Due to continuous erosion and deposition along the banks of the meander, the ends of the meander loop come closer and closer. In due course of time the meander loop cuts of from the river and forms a cut-off lake. It is called an Ox-bow lake.
2. Tick (✔) the correct answers:
(i) Which of the following gases protects us from the harmful rays of the sun?
(a) Carbondioxide.
(b) Nitrogen.
(c) Ozone.
Ans: (c) Ozone.
(ii) The deposit of glacier is called-
(a) Floodplain.
(b) Mushroom rock.
(c) Moraine.
Ans: (c) Moraine.
(iii) Which of the following is a Precipitation in the form of Water?
(a) Rain.
(b) Cloud.
(c) Ice.
Ans: (a) Rain.
(iv) The place where mushroom-shaped rocks are found is-
(a) Desert.
(b) River valleys.
(c) Floodplains.
Ans: (b) River valleys.
(v) The most important atmospheric layer for human being is –
(a) Mesosphere.
(b) Stratosphere.
(c) Troposphere.
Ans: (c) Troposphere.
(vi) The place where Ox-bow lakes are found is –
(a) Polar region.
(b) River valley.
(c) Desert.
Ans: (b) River valley.
3. Match the given items:
|
(a) Trade wind |
(a) Middle course of a river |
|---|---|
|
(b) Glacier |
(b) Local wind |
|
(c) Loo |
(c) Ozone layer |
|
(d) Meandering course |
(d) River of ice |
|
(e) Stratosphere |
(e) Regular wind |
Ans:
|
(a) Trade wind |
(e) Regular wind |
|---|---|
|
(b) Glacier |
(d) River of ice |
|
(c) Loo |
(b) Local wind |
|
(d) Meandering course |
(a) Middle course of a river |
|
(e) Stratosphere |
(c) Ozone layer |
4. Give reasons ( within 50 words):
(i) Wet clothes do not dry up easily in damp weather.
Ans: The humidity level in the atmosphere is already high, so it becomes difficult for moisture to change into vapour. Water vapour in the atmosphere is already heavy so when we try to dry clothes the evaporation process is slow but effective due to the presence of water vapour in the air.
(ii) The floods plains are very fertile.
Ans: 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 materials called ‘sediments’ along its banks. This leads to the formation of a flat fertile “Floodplain.”
(iii) Some desert rocks are mushroom – shaped.
Ans: The wind can blow away the fine lighter dust particles for long distance. But wind cannot blow away the sand particles for long distance. Of course the capability of erosion of such blowing sand particles at certain height is high. Thus, wind is an active agent of erosion and deposition in the desert. That is why one can see rocks with the shape of a ‘mushroom’ in the desert.
(iv) The polar regions are colder that the equatorial region.
Ans: In the equatorial region, tempera- ture is very high and hence always an area of low pressure is formed. The air pressure is measu- red with Barometer machine. The temperature of the Polar Regions is significantly colder than the equatorial regions because the sun’s rays are not directly at the poles.
Q1: What are the major natural forces that shape the Earth’s surface?
A: The Earth’s surface is shaped by wind, water, glaciers, earthquakes, and volcanic activities, which cause weathering, erosion, and deposition.
Q2: How do human activities impact the Earth’s surface?
A: Human actions like deforestation, construction, mining, and industrialization contribute to soil erosion, land degradation, and climate change.
Q3: What is the difference between weathering and erosion?
A: Weathering is the breaking down of rocks into smaller particles, while erosion is the movement of these particles by natural forces like wind and water.
Q4: What role do rivers and glaciers play in shaping landforms?
A: Rivers create valleys, deltas, and floodplains through erosion and deposition, while glaciers carve out U-shaped valleys and transport sediments over long distances.
Q5: Where can I find solutions for all Class 7 Social Science chapters?
A: To access solutions for all chapters, Click Here
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