Page 105 - Social Studies 4

Structure oF
Lesson 4 Unit 5
tHe eartH

Objectives:

On completion of this lesson, students will be able to:
• Explain basic information about the structure of the earth.
• Draw a rough sketch of the earth.

The earth is not exactly round in shape. It looks such as an orange. It is
a little bit flatten both at the North and the South Poles. Similarly, the
middle part of the earth surface is bulged a bit.

The earth is naturally tilted at 23.5 on its axis. Both North and the South
0
Pole have been covered with thick layer of ice. Rest of the earth’s surface
is covered with water and land. There is about 71% of water and 29 % of
land on the earth.

Core, mantle and crust are the three layers of the earth.

a. Core: Core is the central part of the earth. The core is also divided
into two parts. The outer core is in liquid form and the inner core
is in solid form. There are nickel and iron mostly in both outer and
inner core. It is about 5100 km thick. It is very hot.

Megha's Integrated Social Studies - 4 101