Construction Of Earth Gar

Life on the Earth The earth is one of the nine planets, which revolves around the sun. The earth is always in motion it revolve about its own axis. The path in which earth revolves around the sun is called its orbit.It completes one revolution around the sun in 3651/4 days but completes one rotation about its own axis in 24 hours . Due to this rotation different parts of earth face towards sun one by one. That is why day and night occur. Earth is the only planet in the solar system on which life evolves. The existence of life on the earth is possible due to number of special environmental conditions like presence of water, oxygen in the atmosphere ,protective ozone layer around it, and right temperature.

CONSTRUCTION OF EARTH Earth is made up of matter which is not uniformly distributed in it. There are evidences that earth was molten during its early stage.At that stage the heavy elements such as iron settled in the centre of it and light elements came on the surface. This reorganization of various elements according to their densities is called differentiation of earth. On the basis of density of material constituting the earth it is mainly divided into three layers, they are crust, mantle, and core Crust (35-60km)

2900 km

Mantle 3400km

Core

Crust (8-10 km)

CRUST The outermost layer

of the earth

is known

as crust.

It is made of light rocks which mainly consist of silica and aluminum. Its thickness varies from place to place It is maximum in the continental region and minimum under the sea.Its thickness varies from 8km to 10km under the sea . The density of matter present in this layer is very low. Above the earth crust there is atmosphere, which supports life to originate on earth. The earth crust consists of minerals which are essentials for existence and growth of life on earth. These minerals are found deep into earth’s crust . common minerals which we get from earth crust are petroleum products,iron,aluminium ,coal, copper etc. Human beings use all these minerals in their day to day life.

MANTLE The region below the earth crust is called mantle, which is extended to the depth of 2900km below crust. It consists of rocks which are largely made up of magnesium and iron silicate. The density of matter present in this layer is more than density of matter present in the crust. Matter in this layer is in solid state. Some of the rocks present near the bottom of the mantle are in liquid state. These rocks are known as magma.

CORE The innermost layer is called the core of the earth.It consists of the heaviest matter present inside the earth, which are mainly iron and some nickel. Its depth is about 3400km and it is extremely hot. Core is divided in to two parts: the inner core and the outer core. The inner core has solid iron whereas the outer core is in the molten state. Submitted By: Teacher Name:- Mrs Darshna Jindal  StudentsNames:- Sarvesh, Deepak. Renu, Gyanwati Under the Guidance:Teacher Trainer :- Mr.Hari Krishan Bhatt Student Trainer :- Miss Kajli Tandon SESSION :– 2006-2007