This animation explores the 3 main layers of the Earth and tells how they were discovered, what they are, and how the crust differs from the tectonic (lithospheric) plates. [6:20]

Earth's interior is broadly grouped into three main layers on the basis of chemical composition: crust, mantle, and core. An egg analogy is used to show relative thicknesses, and a Big Hunk analogy illustrates how a material of a single...