<span>Crust
</span>
<span>This is the outer layer of the Earth about 10 miles or so thick. Mostly made up of rock and loose material. The crust found underneath continents is 3 times thicker than the crust underneath the oceans.
</span>
<span>Mantle
</span>
<span>The next layer beneath the crust is called the mantle. It extends to a depth of approximately 1,800 miles and is made of a thick solid rocky substance that represents about 85% of the total weight and mass of the Earth.
</span>
<span>The first 50 miles of the mantle are believed to consist of very hard rigid rock. The next 150 miles or so is believed to be super-heated solid rock. Below that for the next several hundred miles, the Earth mantle is once again made up of very solid and sturdy rock materials.
</span>
<span>Outer Core
</span>
<span>Traveling deeper within the Earth, we next would encounter the Earth’s outer core, which extends to a depth of around 3000 miles beneath the surface. It is believed that this outer core is made up of super-heated liquid molten lava. This lava is believed to be mostly iron, and nickel.
</span>
<span>Inner Core
</span>
<span>Finally, we would reach the Earth’s inner core. The inner core extends another 900 miles inward towards the center of the Earth. It is believed that this inner core is a solid ball of mostly iron, and nickel.
</span>
<span>The mantle is made of much denser, thicker material, because of this the plates "float" on it like oil floats on water. Many geologists believe that the mantle "flows" because of convection currents. </span>
Convection Currents
These currents are caused by the very hot material rising, cooling, and sinking over and over again. The next time you heat anything like soup or pudding in a pan you can watch the convection currents move in the liquid. When the convection currents flow in the mantle they also move the crust. The crust gets a free ride with these currents. A conveyor belt in a factory moves boxes like the convection currents in the mantle moves the plates of the Earth.
<span>Magma
</span>
<span>The first question this raises is: what exactly is this "material from the inside"? On our planet, it's </span>magma, fluid molten rock. This material is partially liquid, partially solid and partially gaseous.
<span>Radiation
</span>
<span>Ultraviolet radiation that eats away at the ozone layer
</span>
<span>Hydrosphere
</span>
<span>Welcome to something we like to call the </span>hydrosphere! This is where we talk about the way water moves through the world. W\ater affects everything that happens in life. In Latin, "hydro" means water. Therefore, anything that scientists describe, when it comes to water, is a part of the hydrosphere. That water may be at the bottom of the ocean or in the top layers of the atmosphere; it is all a part of the hydrosphere.
<span>Lithosphere
</span>
<span>The crust is composed of two basic rock types granite and basalt. The continental crust is composed mostly of granite. The oceanic crust consists of a volcanic lava rock called basalt. Basaltic rocks of the ocean plates are much denser and heavier than the granitic rock of the continental plates. Because of this the continents ride on the denser oceanic plates. The crust and the upper layer of the mantle together make up a zone of rigid, brittle rock called the Lithosphere. </span>
<span>Asthenosphere
</span>
<span>The layer below the rigid lithosphere is a zone of asphalt-like consistency called the Asthenosphere. The asthenosphere is the part of the mantle that flows and moves the plates of the Earth.
Hope this helps. :)</span>
