The plate tectonic theory is the theory that proposes that earths outer shell consists of individual plates that interact in various ways and there by produce earthquakes, volcanoes, mountains, and the crust itself.
Evidence supporting the plate tectonics theory starts with paleomagnetism. Which is the magnetic field that has a north and south pole, these magnetic poles align closely, but not exactly, with the geographic poles. Next there are the earthquake patterns. Which is evidence that scientist found a close link between deep focus earthquakes and ocean trenches. Also, the absence of deep focus earthquakes along the oceanic ridge system was shown to be consistent with the new theory. Then there is ocean drilling, which is drilling directly into the ocean floor sediment. The Deep Sea Drilling Project used the drilling ship Glomar Challenger to drill 100 meters into the sediments and underlying crust. Lastly, there are hot spots. Which the mapping of sea floor volcanos in the pacific revealed a chain of volcanic structures extending from the Hawaiian islands to midway island and then north to the Aleutian trench. A rising plume of mantle material is located below the island of Hawaii. Melting of this hot rock as it nears the surface creates a volcanic area, or hot spot. These are the four pieces of evidence for plate tectonics.
The plate tectonic is the theory that explains the structure, composition and internal working of the earth on a world wide scale, while continental drift refers to the theory that the continents all used to be connected in one megacontinents which scientist dubbed Pangaea. Both theories attempt to explain the movement of parts of the earths crust.