NCERT Class 9 Social Science Understanding Society India and Beyond PART-I: Chapter 2 — Shaping of the Earth's Surface
This chapter, "Shaping of the Earth's Surface," from NCERT's Class 9 Social Science textbook "Understanding Society: India and Beyond PART-I," explores the dynamic processes that transform our planet. It introduces the fundamental concept of plate tectonics, explaining how the Earth's crust is divided into moving plates that cause major landforms and phenomena like mountains, earthquakes, and volcanoes. The chapter details the Earth's internal structure, including the crust, mantle, and core, and defines key terms like lithosphere and asthenosphere. It highlights how weathering, erosion, and deposition, alongside crustal movements, create diverse landforms. Understanding these processes is crucial for appreciating the Earth's ever-changing nature and its impact on human life and natural disasters, aiding CBSE students in grasping geological concepts.
Quick info
| Board | CBSE / NCERT |
|---|---|
| Class | Class 9 |
| Subject | Social Science |
| Book | Understanding Society India and Beyond PART-I |
| Chapter | Chapter 2 — Shaping of the Earth's Surface |
| Language | English |
| PDF type | NCERT Textbook |
| Session | CBSE 2026 |
| Reading time | 3 minutes |
| Word count | 552 |
Learning outcomes
- Understand the concept of plate tectonics and its role in shaping the Earth's surface.
- Identify and classify different types of landforms.
- Describe the internal structure of the Earth (crust, mantle, core).
- Explain the processes of weathering, erosion, and deposition.
- Recognize the connection between landforms and natural phenomena like earthquakes and volcanoes.
Vocabulary
| Word | Meaning |
|---|---|
| Plate tectonics | A theory explaining the movement of the Earth's crustal plates. |
| Landform | A natural feature on the Earth's surface. |
| Lithosphere | The rigid outer layer of the Earth, including the crust and upper mantle. |
| Asthenosphere | A semi-molten layer beneath the lithosphere that allows plate movement. |
| Weathering | The breakdown of rocks and minerals on the Earth's surface. |
| Erosion | The process of wearing away and transporting soil and rock. |
| Deposition | The process where eroded material is laid down. |
| Tectonic plates | Large, moving slabs of rock that make up the Earth's crust. |
| Mantle | The layer of the Earth between the crust and the core. |
| Core | The innermost layer of the Earth. |
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Practice questions
- What is plate tectonics? Answer: Plate tectonics is a theory that explains the movement of the Earth's crust, which is broken into large pieces called tectonic plates.
- Name the three main layers of the Earth. Answer: The three main layers are the crust, mantle, and core.
- What is a landform? Answer: A landform is a natural feature on the Earth's surface formed by processes like weathering, erosion, deposition, and crustal movement.
- What is the lithosphere? Answer: The lithosphere is the rigid outer layer of the Earth, comprising the crust and the upper part of the mantle.
- Give examples of landforms. Answer: Examples include mountains, valleys, plateaus, plains, deserts, and coastal features.
Frequently asked questions
What is the main idea behind the theory of plate tectonics?
The theory of plate tectonics explains that the Earth's crust is broken into large pieces called tectonic plates, which move slowly over the molten mantle, causing changes on the Earth's surface.
How are landforms created according to the chapter?
Landforms are created by processes such as weathering, erosion, deposition, and the movement of the Earth's crust.
What are the three main layers of the Earth?
The three main layers are the crust, the mantle, and the core.
What is the difference between the lithosphere and the asthenosphere?
The lithosphere is the rigid outer layer (crust + upper mantle), while the asthenosphere is the semi-molten layer beneath it that allows the lithospheric plates to move.
What are tectonic plates?
Tectonic plates are massive slabs of solid rock that make up the Earth's lithosphere and move slowly over the asthenosphere.
What are some examples of landforms mentioned?
Examples include mountains, valleys, plateaus, plains, deserts, and coastal features.
Related resources
Important topics
Topics covered
NCERT Class 9 Social Science — Understanding Society India and Beyond PART-I — Chapter 2 — Shaping of the Earth's Surface. Verified by NCERT Help Editorial Team. Reviewed on 29 Jul 2026. Last updated 10 Aug 2026.