Science Timeline

Alfred Wegener, Harry Hess & Abraham Ortelius

By: Fabah Biji

Abraham Ortelius was a Dutch map maker who was the first one to think that the continents could have been all one piece. He said that the continents looked like fitting puzzle pieces. He was proved to be right centuries later. Ortelius also drew the first modern atlas called the Theatrum Orbis Terrarum which showed 53 maps which might indicate that the continents were one land mass.

Even though Alfred wasn't the first one to think the continents were all one big land mass, he was scolded about it the most. He was denied by geologists because he presented it poorly even though he was mostly right. Alfred wrote a book about his findings in 1915. Wegener was fascinated by how South America's and Africa's shorelines fit together so perfectly. He also fit together mountains from different countries.

Harry Hammond Hess was a professor who believed many of Alfred Wegener's points in his theory but he had very different opinions about how the plate tectonics moved. He came up with the brilliant hypothesis of seafloor spreading. Seafloor spreading is when magma from the upper mantle flows up onto the seafloor. The magma then covers the deep ocean trenches, creating new seafloor. Hess explained all of this in his book, "History of Ocean Basins" which was a very big contribution to the development of plate tectonics. Harry came up with his hypothesis while fighting in WW2 in the ocean. He was able to do some echo- sounding surveys in the Pacific Ocean. Hess' hypothesis was accepted by the scientific community after other scientists did some tests.

Timeline

Vocabulary

Continental Drift- the movement of continents which moves the crustal plates (Alfred Wegener) Mid Ocean Ridges- a long mountain range on the bottom of the seafloor (Harry Hess) Sea-Floor Spreading- the process were new oceanic crust is formed by magma at mid-ocean ridges, where the magma keeps on replacing the old ocean floor (Harry Hess) Pangaea- a supercontinent made out of all the landmasses in earth (Alfred Wegener) Plate Tectonics- very large sections on earth's surface that move very slowly (Harry Hess)