Alfred Wegener proposed the theory of continental drift at the beginning of the 20th century. His idea was that the Earth's continents were once joined together, but gradually moved apart over millions of years. It offered an explanation of the existence of similar fossils and rocks on continents that are far apart from each other. But it took a long time for the idea to become accepted by other scientists.Before Weg
Contents contributed and discussions participated by Annabelle Cheng
Continental Drifts - 1 views
BBC - GCSE Bitesize: Wegener's theory - 11 views
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Wegener suggested that mountains were formed when the edge of a drifting continent collided with another, causing it to crumple and fold. For example, the Himalayas were formed when India came into contact with Asia.
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se the Earth was cooling down, and in doing so contracted. This was believed to form wrinkles, or mountains, in the Earth's crust. If the idea was correct, however, mountains would be spread evenly over the Earth's surface. We know this is not the case.
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What evidence did Alfred Wegener use to support his theory of continental drift - 18 views
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Alfred Wegener's fully developed theory of continental drift attempted to point out evidences that the continents were once joined into a single continent he called Pangea. Wegener's theory hypothesized that the continents were able to push through the rock of the seafloor to their present positions. As evidence, he noted, as had others before him, of the geographic correlation in coastline perimeters of South America and Africa. This was the feature that led Wegener to investigate for other evidences. His investigations revealed that mountain ranges in South America and Africa, and strata and composition of coal fields in Europe and North America matched or lined up. Additionally, matching reptilian fossils were found on either side of the ocean, indicating that the continents were once joined together. Although he was unable to find a mechanism for his proposed continental drift theory, he also observed that the more shallow an ocean, the younger its geologic age. It wasn't until the 1950's and 1960's, with the discovery of the Mid-Atlantic Ridge, and other sea floor mapping discoveries that Wegener's hypothesis started to become more accepted. The newer science of plate tectonics owes much to Wegener's scientific groundwork.
Wegener and Continental Drift Theory - 15 views
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Alfred Wegener was the scientist who championed the Continental Drift Theory through the first few decades of the twentieth century. Simply put, his hypothesis proposed that the continents had once been joined, and over time had drifted apart. The jigsaw fit that the continents make with each other can be seen by looking at any world map.
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Since his ideas challenged scientists in geology, geophysics, zoogeography and paleontology, it demonstrates the reactions of different communities of scientists. The reactions by the leading authorities in the different disciplines was so strong and so negative that serious discussion of the concept stopped.
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Why did Alfred Wegener's work produce such a reaction? He was much more diplomatic in presenting his theory than Galileo. Although he believed himself to be right and that some of his arguments were compelling, he knew he would need more support to convince others. His immediate goal was to have the concept openly discussed. Wegener did not even present Continental Drift as a proven theory. These modest goals did not spare him. The fact that his work crossed disciplines exposed him to the territoriality of scientific disciplines. The authorities in the various disciplines attacked him as an interloper that did not fully grasp their own subject. More importantly however, was that even the possibility of Continental Drift was a huge threat to the established authorities in each of the disciplines.
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Alfred Wegener - 9 views
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Reaction to Wegener's theory was almost uniformly hostile, and often exceptionally harsh and scathing; Dr. Rollin T
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Part of the problem was that Wegener had no convincing mechanism for how the continents might move. Wegener thought that the continents were moving through the earth's crust, like icebreakers plowing through ice sheets, and that centrifugal and tidal forces were responsible for moving the continents.
Alfred Wegener - Wikipedia, the free encyclopedia - 8 views
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Alfred Wegener first thought of this idea by noticing that the different large landmasses of the Earth almost fit together like a jigsaw.
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The Continental shelf of the Americas fit closely to Africa and Europe, and Antarctica, Australia, India and Madagascar fit next to the tip of Southern Africa.
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He analyzed either side of the Atlantic Ocean for rock type, geological structures and fossils. He noticed that there was a significant similarity between matching sides of the continents, especially in fossil plants.
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Tsunami - 0 views
"Tsunami Speed" - 0 views
Tsunami animation - 0 views
Video: Just how does a tsunami work? (National Geographic) | Seattle's Big Blog - seatt... - 0 views
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