Inside Our Earth

Learning Goals:

The earth is a dynamic planet i.e. it undergoes changes constantly. These changes are:


Interior of the earth

The earth is made up of several concentric layers. Concentric means having a common centre. The earth has one layer inside another.

interiors of earth

Broadly, there are three layers of the earth:

  1. Crust
  2. Mantle
  3. Core

The Crust

It is the outermost layer over the earth’s surface. It is

The main minerals constituting the continental mass are:


The continental mass is also called ‘sial’. The name sial is derived from letters ‘si’ of silicon and ‘al’ of alumina.

The main mineral constituents of the oceanic crust are:

The oceanic crust is called ‘sima’. The root of the word sima is ‘si’ from silica and ‘ma’ from magnesium.

Mantle

It is the layer just beneath the crust and extends up to a depth of 2900 km below the crust.

Core

It is the innermost layer i.e. it is below the mantle. Its radius is about 3500 km. The core consists of outer core and inner core. It is mainly made up of:

The innermost layer is also called ‘nife’. The name nife is derived from the word ‘ni’ from nickel and ‘fe’ from ferrous meaning iron. The temperature and pressure of the central core is very high.



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