By Mikayla Cook
The three layers of the Earth are the crust, the mantle, and the core. The crust is important because it holds up our entire world, supporting plant, animal, and human life. The mantle is important because it holds up and moves the tectonic plates through convection currents. The core is important because moving fluids inside of it create a magnetic field to support our magnetosphere. Without it, we would be hit by Sun particles and cosmic rays. The mantle supports the plates, of which the theory is that the lithosphere is split into a ton of plates and that they move towards, away from, and next to other plates. Those actions are called plate boundaries. There are four different plate boundaries: transform, divergent, convergent, and convergent with subduction. At transform boundaries, the plates grind against each other, both moving in separate ways, creating faults and earthquakes. At divergent boundaries, the plates slide away from each other, creating seafloor spreading and rift valleys. At convergent boundaries, the plates slide towards each other, creating mountains and volcanoes. At convergent boundaries that have subduction, one plate slides under the other, creating trenches. The Ring or Fire is an example of convergent boundaries. It is significant because it is home to about 4/5 of seismic activity, making it the most volcanically active place on Earth. An example of divergent boundaries is seafloor spreading. Seafloor spreading is when the continents drift apart, and magma rises from below the surface, drying instantly and creating new seafloor. This theory was created by Harry Hess. This theory helps scientists prove continental drift because since the continents are spreading apart, new land forms there, and there is only one explanation for that. Convection helps with plate movement because, since heat moves upwards and cold moves down, heated plated move up and cooled plates move down. This is called subduction, or convergent with subduction. When the plates move away, towards, and next to each other, it is called continental drift. Continental drift is just the movement of the tectonic plates across the surface of the Earth. This theory was created by Alfred Wegener. Scientists proved continental drift because they found the fossils on different continents and they also noticed that the continents fit together like a puzzle. Plate tectonics are fascinating, and they help explain a lot of our questions.