NCERT Book Class 9 Social Science (Understanding Society India and Beyond PART-I) Chapter 2 Shaping of the Earth’s Surface

Chapter 2

Shaping of the
Earth’s Surface
The Big Questions
1. What shapes the Earth’s surface?
2. What is plate tectonics? What are the effects of plate movement?
3. How are landforms formed and how are they classified?
4. How are humans and other living beings connected to these
landforms?
5. How do disasters associated with different landforms impact
human lives?

The Earth’s surface is not consistent; it is constantly being Landforms:
transformed by powerful forces acting from within and on the A landform
surface of the planet. One of the most important ideas that explains is a natural
feature on the
these changes is the theory of plate tectonics, which describes how Earth’s surface
large pieces of the Earth’s crust move slowly over the molten mantle. formed by
The movement of these plates gives rise to various landforms, such processes, such
as mountains, volcanoes, plains, and valleys. Understanding plate as weathering,
erosion,
tectonics and landforms helps us explain natural phenomena like deposition, and
earthquakes, volcanic eruptions, and the formation of continents the movement
and oceans, and allows us to better appreciate the dynamic nature of the Earth’s
of the Earth. crust. Examples
of landforms
include
Plate Tectonics mountains,
valleys, plateaus,
Plate tectonics is an important theory, given by W.J. Morgan, in earth plains, deserts,
science, that explains the movement of the Earth’s crust. According and coastal
features.
to this theory, the outermost layer of the Earth is not one single piece
but is broken into several large and small pieces called tectonic
plates. These plates move slowly over the semi-molten layer beneath
them and are responsible for major physical features and natural
phenomena, such as mountains, earthquakes, and volcanoes.