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Homework Due Monday
It was a 3 choice assignment.
Read the article in Science World and take split page notes. Mission Mars is the article. If you do not have it, then I suggest you go to Blackboard.monroe.edu and use your password to do one of the other 2 possibilities.
Ms. Long
Next week, there will be a vocab. test over the words from the presentations (which you are still presenting).
Happy Thanksgiving
Due Tuesday Nov 13th…all groups
An explanation of Continental Drift. There are 2 ways to present this information.
1) Write your description as a letter to the editor of a local paper explaining what Continental Drift is: define it, give the scientific evidence for it
2) Write the test for a children’s book explaining Continental Drift. You do not need to include the pictures, simply write the text for each page; above the text write – here I will put a picture of the continents as they are now, or here I will put a picture of the center of the Earth.
You should include the following vocabulary: plate tectonics; continental plates, convection, ring of fire, fossil record
Note: There is no vocab quiz this week. It will be next Monday and cover words learned in class this week related to the 3 kinds of rocks and crystals.
No Homework due Monday for Blue, Green has the Wegener notes
Due Thursday for all Groups: A one page Time Magazine’s Man of the Year: Alfred Wegener
- based on the example in class (or look on-line for a Time Mag example), make a colorful informative cover for Time Magazine with Alfred Wegener as the Man of the Year
- include some basic information from our class notes and your reading
- the cover is largely an illustration (you may copy paste a picture), but should have key information about Why he is Man of the Year, I.E. Science Proves Wegener’s early theory about Continental Drift
Vocab quiz Friday on words from last week. See vocab site for words.
All students must have their lab notebooks with them in class on a regular basis. Tuesday, Blue and Wed, Green, will have an open note test on material presented in class.
Wednesday: Read the hand-out on Wegener, take split page notes in your lab notebooks.
ALFRED WEGENER
(1880-1930)
German climatologist and geophysicist who, in 1915, published as expanded version of his 1912 book The Origin of Continents and Oceans. This work was one of the first to suggest continental drift and plate tectonics. He suggested that a supercontinent he called Pangaea had existed in the past, broke up starting 200 million years ago, and that the pieces “drifted” to their present positions. He cited the fit of South America and Africa, ancient climate similarities, fossil evidence (such as the fern Glossopteris and mesosaurus), and similarity of rock structures..
The Meteorologist Who Started a Revolution
By Patrick Hughes
“Utter, damned rot!” said the president of the prestigious American Philosophical Society.
“If we are to believe [this] hypothesis, we must forget everything we have learned in the last 70 years and start all over again,” said another American scientist.
Anyone who “valued his reputation for scientific sanity” would never dare support such a theory, said a British geologist.
Thus did most in the scientific community ridicule the concept that would revolutionize the earth sciences and revile the man who dared to propose it, German meteorological pioneer and polar explorer Alfred Wegener. Science historians compare his story with the tribulations of Galileo.
A Geographic Jigsaw Puzzle
“Doesn’t the east coast of South America fit exactly against the west coast of Africa, as if they had once been joined?” wrote Wegener to his future wife in December 1910. “This is an idea I’ll have to pursue.”
The following fall Wegener came across scientific papers promoting the prevailing theory that Africa and South America had once been connected by a continent-size land bridge that had since sunk into the sea. They cited as evidence fossils of identical animals that had lived in both areas simultaneously hundreds of millions of years ago. Wegener realized that the forces within the Earth would never allow such a large piece of land to sink. Therefore, he knew that the theory of the land bridge could not be correct.
Wegener was fascinated by the fact that fossils and rocks now far apart appear to have been the same and searched out other papers about such continental coincidences. As he read, his earlier idea that the continents had once been joined became a conviction he would boldly champion for the rest of his life.
On January 6, 1912, Wegener startled a meeting of the Geological Association in Frankfurt with his radical theory. Dismissing the concept of sunken land bridges, he proposed instead a grand vision of drifting continents and widening seas to explain the evolution of Earth’s geography.
Wegener had launched a revolution.
The Education of a Revolutionary
Alfred Wegener was born in Berlin on November 1, 1880. He studied the natural sciences at the University of Berlin, receiving a doctorate in astronomy in 1904. He did not pursue a career in astronomy, however, but turned instead to meteorology, because the telegraph, Atlantic cable, and wireless were fostering rapid advances in storm tracking and forecasting.
In 1905 Wegener went to work at the Royal Prussian Aeronautical Observatory near Berlin, where he used kites and balloons to study the upper atmosphere. He also flew in hot air balloons; indeed, in 1906 he and his brother Kurt broke the world endurance record by staying aloft for more than 52 hours. From the beginning he was an adventurer.
Thanks to his upper-air work, Wegener was invited to join a 1906 Danish expedition to Greenland’s unmapped northeast coast. He was thrilled: As a youth he had dreamed of exploring the Arctic, attracted by both the scientific and physical challenges. During this expedition Wegener became the first to use kites and tethered balloons to study the polar atmosphere.
When he returned to Germany, Wegener’s Arctic research earned him a position at the small University of Marberg where, beginning in 1909, he lectured on meteorology, astronomy, and “astronomic-geographic position-fitting for explorers.”
Both students and professors were impressed by the clarity of the young meteorologist’s thinking and by his ability to explain difficult concepts in simple terms.
In 1912, the year of his continental-drift presentations, Wegener also undertook a scientific expedition to Greenland. His four-man expedition “escaped death only by a miracle” while climbing a suddenly calving glacier on the northeast coast, then became the first to overwinter on the ice cap. The following spring, they barely survived the longest crossing of the great ice sheet ever made, traversing 750 miles of barren snow and ice rising to heights of 10,000 feet.
During these perilous adventures, Wegener collected volumes of unique scientific data. (Field notes!!) The resulting publications established him as one of the world’s leading experts on polar meteorology and glaciology. When he returned to Marberg University, Wegener resumed work on continental drift, using all the scientific evidence he could find to support his theory.
Using this pioneering interdisciplinary approach, Wegener wrote one of the most influential and controversial books in the history of science: The Origin of Continents and Oceans, published in 1915. Because of the First World War, Wegener’s book went unnoticed outside Germany. In 1922, however, a third (revised) edition was translated into English, French, Russian, Spanish, and Swedish, pushing Wegener’s theory of continental drift to the forefront of debate in the earth sciences.
The Origin of Continents and Oceans-Wegener’s Theory
Wegener began by demolishing the theory that large land bridges had once connected the continents and had since sunk into the sea as part of a general cooling and contraction of the Earth. He pointed out that the continents are made of a different, less dense rock (granite) than the volcanic basalt that makes up the deep-sea floor. (Therefore the less dense rocks would never sink into the ocean). Wegener also noted that the continents move up and down to maintain an overall balance in a process called isostasy. As an example of this he cited the sinking of Northern Hemisphere lands under the weight of continental ice sheets in the last ice age, and their rise since the ice melted some 10,000 years ago. (We’ll discuss this when we study glacial geology.)
Wegener also offered a more likely explanation for mountain ranges. Wegener said they formed when the edge of a drifting continent crumpled and folded–as when India hit Asia and formed the Himalayas.
He also noted that when you fit Africa and South America together, mountain ranges (and coal deposits) run uninterrupted across both continents, writing:
It is just as if we were to refit the torn pieces of a newspaper by matching their edges and then check whether the lines of print ran smoothly across. If they do, there is nothing left but to conclude that the pieces were in fact joined in this way.
By his third edition (1922), Wegener was citing geological evidence that some 300 million years ago all the continents had been joined in a supercontinent stretching from pole to pole. He called it Pangaea (all lands), and said it began to break up about 200 million years ago, when the continents started moving to their current positions.
The Wrath of Science
Except for a few converts, the international geological community’s reaction to Wegener’s theory was militantly hostile. Moreover, most of the blistering attacks were aimed at Wegener himself, an outsider who seemed to be attacking the very foundations of geology. As a result of his ideas, he lost his position at his German University.
In 1926 Wegener was invited to an international symposium in New York called to discuss his theory. Though he found some supporters, many speakers were sarcastic to the point of insult. Wegener said little. He just sat smoking his pipe and listening.
Scientifically, of course, Wegener’s major problem was finding a force or forces that could make the continents “plow around in the mantle,”, At the time, there was not enough understanding of the Earth to explain how the continents could move.
Wegener noted, however, that one thing was certain:
The forces that move continents are the same as those that produce great fold-mountain ranges, faults and compressions, earthquakes, volcanoes, [ocean] transgression cycles and [apparent] polar wandering are undoubtedly connected on a grand scale.
Wegener’s final revision cited supporting evidence from many fields, including testimonials from scientists who found his hypothesis resolved difficulties in their disciplines much better than the old theories. Climatology was one such discipline. He showed that fossil recorded indicated that many areas of the world once shared the same climate because they were once together and part of the same climate. Many people accepted the logic of this idea, but they still could not accept the theory.
As a result, most geologists eventually dismissed his theory as a fairy tale or “mere geopoetry.”
Vindication of a Visionary
Despite general rejection, Wegener’s compelling concept continued to attract a few advocates over the next several decades. Then, beginning in the mid-1950s, a series of confirming discoveries in paleomagnetism and oceanography finally convinced most scientists that continents do indeed move. Moreover, as Wegener had predicted, the movement is part of a grand scale process that causes mountain-building, earthquakes, volcanic eruptions, sea-level fluctuations, and apparent polar wandering as it rearranges Earth’s geography.
Geologists call the process “plate tectonics,” after the large moving plates that form the planet’s outer shell. Now we accept that Alfred Wegener was right in most of his major concepts..
During the last few decades, Alfred Wegener has finally gotten the recognition he deserves. Unfortunately, as with most visionaries, it must be posthumous praise.
