1. Inner Core: The densest layer, primarily made of solid iron and nickel.
2. Outer Core: Less dense than the inner core, primarily composed of liquid iron and nickel.
3. Lower Mantle: Solid but behaves like a very viscous fluid over geological timescales. Composed of silicate minerals.
4. Upper Mantle: Also solid but with a more plastic consistency. Contains minerals like olivine and pyroxene.
5. Crust: The least dense layer, composed of igneous, metamorphic, and sedimentary rocks. There are two types: oceanic crust (thinner and denser) and continental crust (thicker and less dense).
Important Note: While the inner core is solid, the extreme pressure is what makes it behave like a solid. If you were to bring a piece of the inner core to the surface, it would be a liquid.
