Kids Research Express

Earth’s surface is the outermost layer of the planet. It includes the hydrosphere, the crust, and the biosphere. See: Hydrosphere Crust Biosphere Changes to Earth’s Surface

Opposing this tendency toward leveling is a force responsible for raising mountains and plateaus and for creating new landmasses. These changes to Earth’s surface occur in the outermost solid portion of Earth, known as the lithosphere . The lithosphere consists of the crust and another region known as the upper mantle and is approximately 65 to 100 km (40 to 60 mi) thick. Compared with the interior of the Earth, however, this region is relatively thin. The lithosphere is thinner in proportion to the whole Earth than the skin of an apple is to the whole apple. Scientists believe that the lithosphere is broken into a series of plates, or segments. According to the theory of plate tectonics, these plates move around on Earth’s surface over long periods of time. Tectonics comes from the Greek word, tektonikos, which means “builder.” According to the theory, the lithosphere is divided into large and small plates. The largest plates include the Pacific plate, the North American plate, the Eu