The History of the Atom 5: The Modern Theory investigates the development of modern atomic theory. Greek philosophers Leucippus and Democritus first developed the concept of the atom in the 5th century B.C.E.
Therefore, based on the concepts of the continental drift and other developing ideas at the time, a general theory was developed, which is now known as the plate tectonics. Plate Tectonics. Plate tectonics is the theory explaining the motion of the outer crust or the lithosphere of earth. Lithosphere is divided into tectonics plates. Two main types of tectonics plates are the oceanic crust and continental crust. Oceanic crust is mainly composed of Silicon and magnesium, hence called SIMA.
An important piece of plate tectonic theory is the continental drift idea. This was developed in the early part of the 20 th century, mostly by a single scientist, Alfred Wegener.lthough Wegener's evidence was sound, most geologists at the time rejected his hypothesis of continental drift. These scientists argued that there was no way to explain how solid continents could plow through solid oceanic crust.