Question

Why is the earth layered and how is each layer different?

Answer 1

Hint: The Earth has three broad layers - the innermost being the core, then the mantle, and the outermost being the crust. At times, the core is divided further into two parts - the inner core and the outer core. The temperature decreases as one moves away from the core to the crust.

Complete answer: The Earth was extremely hot and as it cooled, the denser materials gravitated towards the centre while the less dense materials moved towards the surface. This formed the layers that we know today. That is why, the lightest materials like the rocks and the granites are found in the outermost layers while the inner layers are heavier materials like nickel and iron.
-The inner core is the hottest layer, and located at the centre of the Earth. It is solid and has a temperature of upto 5,500 degrees Celsius.
-The outer core envelopes the inner core. Its temperature varies between 4,000 to 9,000 degrees Fahrenheit. It is 1,400 miles thick and is located 1,800 miles below the crust. It is mainly constituted by molten metals.
-The mantle is the widest layer with a thickness of 2,900 km. It consists of very hot, molten rock called magma.
-The crust is a very thin layer with a thickness varying from 0 to 60 km. This is where we live. -The crust has two kinds: the continental crust and the oceanic crust, which provides base to land and oceans, respectively.

Note: Temperatures and pressures increase as one goes deeper into the layers. The crust is cool and solid with minimum pressure exerted upon it. The mantle is hotter and is molten. The core is the hottest of all, but solid because of the extreme pressure from the above layers.