Page 106 - Social Studies 4

b. Mantle: The thickest part of the earth’s mantle found in between
crust and the core of the earth. It is in semi-solid form of magma
such as toothpaste. It is about 2800-2900 km thick.

c. Crust: The outer most part of the earth is called crust. It is the
thinnest layer of the earth. It is made up of soil, rock and other
minerals. It is about 100 km thick.

The crust has mountains, plains, oceans, valleys, rivers, deserts,
etc.

Core

Mental

Crust

Our earth surface is covered with a layer of gases (air). It is called
atmosphere. The air (oxygen) contained in the atmosphere helps us to
breathe. The different living beings are found on the earth. Thus, the
earth is also called a living planet.

Glossary

flatten - become flat or uniform
tilted - move or cause to move into a sloping position
bulged - a rounded swelling
exactly - accurately; emphasize the accuracy of a figure or
description
contained - be made up of a number of things
axis - an imaginary line about which a body rotates

Teaching instruction: Help the children to make them understand the structure of the earth by comparing
with boiled egg and orange for its shape.

102 Megha's Integrated Social Studies - 4