Our world is an amazing thing. Scientists have been working to understand as much as possible about our earth, including its changes. Plate tectonics is a relatively recent idea that explains how the surface of our earth changes. Our earth is constantly changing, the first theories on plate tectonics have developed over the years; From Alfred Wegener's theory of continental drift to Harry Hess's theory of seafloor spreading, scientists have expanded knowledge of the ever-changing Earth. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an Original Essay The crust and mantle of our earth are constantly in motion. Different pieces, or plates, move at different times. If you look at the Himalayan mountains, you can easily see how the surface of the earth changes. Mountains grow a few centimeters in height each year when the Eurasian and Indian plates collide. The magma closest to the center of the earth is heated. As it approaches the surface it decreases in heat and falls; thus creating a convection cell. As the circle rotates, it pushes the Earth's surface. This is the cause of plate tectonics. The first idea of ​​plate tectonics came from the scientist Alfred Wegener. Alfred Wegener came up with the idea of ​​Pangea, or super earth. The idea of ​​Pangea is the concept that all landmasses of the earth were once a super continent and there was one giant ocean. Wegener believed that over time the continents had somehow drifted apart. His concept was not widely accepted at the time, even though he had three main pieces of evidence. The first is that the continents seemed to fit together like a puzzle. As pointed out in class, this is probably his most important piece of evidence. His second proof is that mountain ranges and deserts coincide where continents fit together. His third piece of evidence is that similar fossils were found in both Africa and South America; this would imply that at some point the two continents were next to each other. His idea was not popular but was eventually proven, as was Harry Hess' idea. Harry Hess came up with the idea of ​​seafloor spreading. We studied the largest underwater mountain range. The Mid-Atlantic chain, he discovered, is actually a large chain of constantly erupting underwater volcanoes. As magma escapes, it pushes the current seafloor and adds to it. He found that the sea floor was being expanded. Rocks within the seabed record the attraction exerted on them by the magnetic poles. The earth changes its magnetic pull every thousand years, so rocks attracted to the north or south pole are marked black or white, respectively. When he noticed the lines, the zebra stripes, he concluded that the seabed is newer in some parts than others. Please note: this is just an example. Get a custom paper from our expert writers now. Get a custom essay These two theories have become the modern concepts of plate tectonics. Plate tectonics is still a relatively new field of study. Scientists are still trying to unravel the mysteries of plate tectonics. We know that the earth is constantly moving and that mantle convection is the cause. Hess and Wegener must be appreciated for being pioneers in this new field of plate tectonics.