Explain the theory of plate tectonics. Describe the different types of plate boundaries?

Plate tectonic theory states that the earth's outer shell is divided into several plates that glide over the mantle, the rocky inner layer above the core.

There are three kinds of plate tectonic boundaries: divergent, convergent and transform boundaries.

A divergent boundary occurs when two tectonic plates move away from each other. Along these boundaries, lava spews from long fissures and geysers spurt superheated water.

A convergent boundary is formed when two plates come together. The impact of the two colliding plates buckles the edge of one or both plates up into a rugged mountain range, and sometimes bends the other down into a deep seafloor trench.

A transform plate boundary is formed when two plates slide over each other. Natural or human made structures that cross a transform boundary are offset. They get split into pieces and carried in opposite directions.