There are 5 different layers of Earth. These are the crust, which is solid; the outer mantle, which is liquid; the inner mantle, which is solid; the outer core, which is liquid; and the inner core, which is solid.

Continental drift theory was theorized by Alfred Wegener in 1912. He noticed that South America and Africa had a puzzle piece appearance, as if they split apart from one another. He also recognized fossil evidence such as Glossopteris (fern like fossil) and Mesosaurus (reptile like fossil), as well as noticing that Pangaea split into Laurasia and Gondwanaland.

Sea floor Spreading was identified by Harry Hess in the 1960’s. His evidence was magnetic bands of alternating reversed polarity, and that rocks are younger near the ridge.