The Layers Of Earth


The Earth comprises of four separate layers. Most of the geologist believes that as the Earth cooled the heavier, the materials denser sank into the center, and the lighter ones rose towards the top. Due to this, the outermost layer is made of lightest materials such as rocks and granites and the innermost layer consists of nickel and iron. Let’s discuss different layers of earth.

What are the different layers of the Earth?

Layers Of Earth

Our Earth consists of four different layers namely:

  • Inner core
  • Outer core
  • Mantle
  • Crust
  1.  Inner Core:

It is the center and the hottest layer of the Earth. The inner core is solid and made up of iron and nickel with temperature up to 5,500oC. Due to its immense heat energy, the inner core is more like the engine room of the Earth.

  1.  Outer Core:

The outer core of the Earth is similar to a very hot ball of metals, whose temperature is around 4000 oF to 9000oF. It is so hot that the metals inside are all in the liquid state. The outer core is located around 1800 miles under the crust and approximately 1400 miles thick. It is composed of metals such as iron and nickel. The outer core surrounds the inner core.

The inner core has pressures and temperatures so high that the metals are squeezed together and not able to move like a liquid, but are forced to vibrate instead of solid.

  1. Mantle:

Mantle is the widest section of the Earth. Its thickness is approximately 2,900 km. Mantle is mainly made up of semi-molten rock known as magma. The rock is hard in the upper part of the mantle, but lower down the rock is softer and begins to melt.

The mantle is located directly under the Sima. The mantle consists of very hot and dense rock. This layer of rock flows like asphalt under heavy weight. This flow is because of the greatest temperature differences from the bottom to the top of the mantle. The reason behind the plates of the Earth move is the movement of the mantle. Its temperature varies between 1600 oF at the upper part to 4000 oF near the bottom.

  1. Crust:

The crust is the outer layer where we live. The thickness is around 0-60 km. It’s a solid rock layer divided into two types:

  1.    Continental crust covers the land and,
  2.    Oceanic crust covers water.

The crust is the most widely studied and understood. Mantle is hotter and capable of flowing. The outer and inner core are much hotter with great pressures that you can be squeezed into a ball smaller than a marble if you are able to go in the center of the Earth.


Practise This Question

Two plates of the same area and the same thickness having thermal conductivities k1 and k2 are placed one on top of the other. The top and bottom faces of the composite plate are maintained at different constant temperatures. The thermal conductivity of the composite plate will be