This model shows Globe internal structure. It shows the Earth’s crust, mantle, the outer centrosphere and the inner centrosphere. The different layers are labelled for easy identification. A knowledge of earth’s interior is essential for understanding plate tectonics. The layers of theEarthcan be defined by their chemical and their rheological properties. Earth has an outer silicate solid crust, a highly viscous mantle, a liquid outer core that is much less viscous than the mantle. As well as a solid inner core. Each of the layers differ chemically and mechanically. The further you get to the core of the Earth, the hotter it gets.