1. Crust:
* Chemical Composition: Primarily composed of Oxygen (O), Silicon (Si), Aluminum (Al), Iron (Fe), Calcium (Ca), Sodium (Na), Potassium (K), and Magnesium (Mg).
* Physical Properties:
* Oceanic Crust: Thinner, denser, and younger than continental crust. Primarily composed of basalt and gabbro.
* Continental Crust: Thicker, less dense, and older than oceanic crust. Primarily composed of granite and granodiorite.
* Rigid and brittle, with a relatively low density.
2. Mantle:
* Chemical Composition: Primarily composed of silicate minerals, including olivine and pyroxene, with smaller amounts of iron and magnesium.
* Physical Properties:
* Upper Mantle: Solid but behaves like a viscous fluid over long periods.
* Lower Mantle: Solid and denser than the upper mantle.
* Solid, but exhibits some plasticity, with a higher density than the crust.
3. Outer Core:
* Chemical Composition: Composed primarily of liquid iron (Fe) and nickel (Ni) with smaller amounts of sulfur (S), silicon (Si), and oxygen (O).
* Physical Properties: Liquid, with a very high density and extremely hot temperatures.
4. Inner Core:
* Chemical Composition: Composed primarily of solid iron (Fe) with a small amount of nickel (Ni).
* Physical Properties: Solid, extremely dense, and incredibly hot. The extreme pressure within the inner core is the primary factor preventing the iron from melting, despite the high temperatures.
Key Points:
* Density increases with depth. The inner core is the densest layer, while the crust is the least dense.
* Temperature increases with depth. The inner core is the hottest layer, while the crust is the coolest.
* Composition changes with depth. The crust is primarily composed of silicate minerals, while the core is primarily composed of iron and nickel.
* Physical properties vary with depth. The mantle behaves like a viscous fluid, while the outer core is liquid and the inner core is solid.
This is a simplified model, and each layer has further subdivisions with varying properties. However, it provides a general understanding of the major layers of the Earth and their key characteristics.
