Final answer:
The movement of Earth's mantle and tectonic plates is driven by mantle convection, a process where thermal energy causes the rise of warm material and sinking of cool material, moving plates at a rate comparable to fingernail growth.
Step-by-step explanation:
The movement of the mantle and its plates takes place in Earth's interior through the process of convection. Earth's crust and upper mantle, known as the lithosphere, are broken into several large tectonic plates. These plates float on the semi-fluid asthenosphere beneath them. The movement of these plates is driven by the process of mantle convection, which is a result of thermal energy transfer from Earth's hot core to its cooler mantle. This heat transfer causes warmer, less dense material to rise, and cooler, denser material to sink. These movements drive the tectonic plates above, leading to various interactions at plate boundaries, including the movement apart of plates, as seen in the Atlantic Ocean, and the collision and subduction of plates, such as off the western coast of South America.
This process is responsible for a host of geological phenomena including earthquakes, volcanic activity, mountain formation, and oceanic trench formation. The rate of movement of these plates is typically a few centimeters per year, similar to the rate of fingernail growth.This concept is fundamental to the field of geology, forming the basis of our understanding of many geological processes, much like the theory of evolution in biology or the concept of gravity in physics.