Special Earth

The Structure of earth

The earth is made up of four main layers : Crust, Mantle, Outer Core, and Inner Core.

Crust
It is the upper portion of the earth where we live and this layer is about 5 to 50 km thick.The temperature increases by 1oC per kilometer
Mantle
The next layer is mantle, which is composed mainly of ferro-magnesium silicates and so hot with the temperature ranging upto 1600o C. it is about 2900 km thick and is separated into the upper and lower mantle.
Outer Core
The outer core is about 2300 km thick mainly consists of molten materials of Iron and nickel with the temperature ranging from 2000oC to 5000oC. Earth’s magnetic field is believed to be controlled by the liquid outer core.
Inner Core
It is about 1200 km thick and has solid iron.

Mountain

Folded mountains take shape when two continental plates ram into each other, compressing and uplifting the rock. The height of the mountain depends upon the type of the rock and the intensity of the collision. The Appalachian mountains, The Alps and the Himalayas are all folded mountain ranges.

Volcano

Volcano forms when molten rock(magma) from the interior of the earth reaches the surface. It erupts either as a stream of liquid rock(called Lava when it appears at the surface) or as ash and builds up over the time into a mountain in conical shape.

Atmosphere

The atmosphere consists of five layers: troposphere, stratosphere, mesosphere, thermosphere and exosphere. The atmosphere which extends up to 700 km, protects us from the sun’s harmful rays and keeps earth from getting too cold or too hot.

The Troposphere
This lowest layer, closer to earth varies in height depending upon the temperature of the air. It is about 16 km at the warm equator and only 9 km at poles.

The stratosphere
It is extended upto 50 km from the earth and has most of the ozone layer, which absorbs the ultraviolet rays from the sun and the air warms up to 40oc.

The mesosphere
It is the thick coldest layer. It does not absorb much of ultraviolet rays and here the temperature drop to -90oC. T

The thermosphere
It is a very thin layer extends upto 480 km. It absorb the sun’s ultraviolet rays and it heats the thermosphere upto 1480oC.

The exosphere
The fifth and the last layer of the atmosphere which fades in to the space contains no air. Its temperature can reach upto 1650oC