The Continental Drift Revolution
Amber Hayward
“A conviction of fundamental soundness of the idea took
root in my mind”.
-Alfred
Wegener, The Origin of Continents and Oceans.
Alfred Wegener was trained as an astronomer, but became interested in the science of weather and climate. Much of his scientific career was spent working in the field of meteorology, and he established the use of hot air balloons in weather research. Because of his work he was selected to go on three separate missions to Greenland to conduct weather related research. His interest in the earth sciences would eventually lead him towards proposing one of the most revolutionary scientific theories since Galileo proposed the earth orbited the sun.
Many aspects of the earth sciences field fascinated Wegener. He noted the shapes of the continents and how they seemed to fit together, but he could not yet explain why. In 1911, he found a scientific paper with a list of identical prehistoric fossils of plants and animals found in South America and Africa. Wegener’s attention was captured by the details of the paper, and he began piecing together the basis of his theory of continental drift.
When war broke out in 1914, he was drafted into the German army, and was injured almost immediately. During his recovery, and his subsequent work with the German army’s weather service, he began to look for data to support his theory. He obtained his evidence from the fields of paleontology (the study of extinct plants & animals), climatology (the study of weather over a period of time), meteorology (the study of weather), geology (the study of rocks & processes that shape earth), and soil science (the study of dirt & sediments).
Wegener’s theory suggested that about 300 million years ago, the continents had formed as a single mass, which he called Pangaea, meaning all lands. Eventually, over millions of years, Pangaea split apart into the continents, and the continents had continued to move apart ever since. Wegener identified two different forces that could power their movement.
Unfortunately Wegener was wrong. The forces he suggested were not strong enough to move the continents, and other geologists jumped at the chance to point out the faults of the theory. They argued that Wegener was an outsider in the field, whose findings did not back his theory. Never before had a scientist combined data from different fields together to create a geological theory. To top it off, Wegener’s theory would change the way scientists studied the earth’s processes completely. Previously geologists thought that the continents stood still and that they had been connected by land bridges that had collapsed. How could continental drift be true?
Wegener stood by his theory though out his lifetime, and became even more determined to find more evidence to support his position. The controversy continued for many years after Wagener died while on his third, and final journey to Greenland, in 1930. Many years later, the work of geologists, Harry Hess, and J.Tuzo Wilson, provided the missing pieces to Wegener’s puzzle and proved the basis of his theory to be correct. Hess discovered sea floor spreading. This is where magma coming up from inside the earth, cools in the ocean, and becomes bigger. This creates a force that wedges the continents slowly apart.
Another scientist, J. Tuzo Wilson, combined the theories of continental drift and sea floor spreading, to give us the theory of plate tectonics. Plate tectonics is based on the idea that the mass of Pangaea broke into pieces that float on top of a molten under layer and move in about in relation to each other. Sometimes when they bump into each other an earthquake can occur or a volcano can form. This is the way we explain most of the earth’s processes today.
Through the work of these scientists Wegener was finally given the credit he deserved. Almost thirty years after his death he was recognized for his courage and determination in presenting a theory that would change the way we look at the processes of the earth forever.
Grade 7 Unit E: The Planet Earth
Science 20 Unit 1: The Changing Earth
1) What is a theory?
2) How did Wegener’s theory change the way we view earth science?
3) Why was it so difficult for other scientists to accept the concept of continental drift?
4) What was missing from Wegner’s argument for continental drift?
5) Do you think Wegener was a good scientist? Why or why not?
Note:
Reading and questions would need to be adapted depending on the age group they are given to (Science 7 students vs. Science 20 students). If I used this for a Science 7 class I would expect that they would have some basic science knowledge as this is the last unit in science 7, but I would probably do this with them in class so that I could address any problems with science words, etc., immediately.
References
Garrison, T. (1999). Oceanography: an invitation to marine science (3rd ed.).
U.S.A.: Wadsworth Publishing Co., pg. 60 –83.
Alfred Lothar Wegener: Moving Continents
http://pubs.usgs.gov/publications/text/Wegener.html
Alfred Wegener (1880 – 1930)
http://earthobservatory/nasa.gov:81/Library/Giants/Wegener/wegener
Alfred Wegener (1880 – 1930)
http://www.ucmp.berkeley.edu/history/wegener.html
Plate Tectonics: The Rocky History of an Idea