The earth has 4 layers: the crust, mantle, inner core and outer core. Some scientists divide the mantle layer into 2 different layers: upper mantle and lower mantle.
The inner core of the earth, as the name suggests, is at the centre of the earth. It is made off metals. The pressure in the inner core is so big that it stays as a solid core. The temperature is almost 5000 C (earth’s temperature on the surface is generally around 20 C) and the pressure is 3,000,000 times more than the air pressure on earth’s surface!
The outer core is not a solid. This layer is liquid because the pressure is not as large as the inner core, but the temperature is still around 4000 C.
This article was produced by PTW Volunteer Chirag Lodhia, Director of PTW