World changing wanderer
Alfred Wegener (1880-1930) was a scientist in the heroic mode, a renowned arctic explorer who died a hero in temperatures of minus-50 degrees Celsius and an adventurer who made record-breaking flights in hydrogen balloons.
But today he is mostly remembered for the discovery he made in the University of Marburg library. Looking at a friend's new atlas, he noticed, as had many before him, that the coastlines of Africa and South America matched as if they were pieces of a jigsaw. Perhaps, he thought, they had once been part of a giant proto-continent.
At first he dismissed this idea as ridiculous, but when he came across a compendium of fossils showing that the animals and plants of South America and Africa had once been the same, he became convinced his idea was right.
He then found more evidence for his now accepted theory of continental drift.
Wegener's life and thoughts can be a valuable topic for ideas and evidence (Sc1) in science at GCSE. A brief description of what he did may also help to add colour to the start of a lesson on changes to the Earth and atmosphere (Sc3) (see box, right).
Classroom activities could include mimicking Wegener by manipulating a home-made paper continental jigsaw to form the one large proto-continent Wegener called Pangaea, and using his method of colour-coding his pieces to show matches of evidence. This could include:
* mountain chains that stop on one side of the ocean to continue on the other
* US coal seams matching British seams of the same age
* the fossils of the small dinosaur mesosaurus and the plant glosopteris found in Africa and South America
* matching rocks of the same type and age on opposite coasts thousands of miles apart
* identical worms and snails found each side of the Atlantic.
For Wegener, the most convincing evidence was from his measurement of longitude. By comparing his readings of the position of an island off Greenland with earlier measurements taken at the same place, he discovered Greenland had moved west by 1,000 metres in 84 years (actually, his measurements were inaccurate, Greenland moves west by a few centimetres a year).
Wegener recorded his evidence in a book called The Origins of Continents and Oceans. Each of four editions contained more detailed evidence than the last. It was translated into several foreign languages - which was when the trouble started.
Basically, geologists laughed. Wegener was not a geologist, yet he had the audacity to tell them they were wrong. Their favoured reason for the matching of the fossils - a prehistoric land-bridge linking the continents - did not make sense. It was impossible for land to bob up and down like that, Wegener said, but it could drift. As he wrote each edition, he was sure geologists would accept his theory, but they never did. The Astronomer Royal was one detractor. He declared that the Earth was solid so there was no way the continents could drift like icebergs through the mantle.
Everything came to a head in a symposium in 1926 in New York. The international delegates took it in turns to ridicule Wegener's ideas. One man questioned the fit, another the fossil evidence, another his explanation of mountains. The arguments went on and on. They called it a fairy tale and the work of a poet. Excerpts would make entertaining reading for students working on AS Science for public understanding.
Wegener wasn't at the conference but he answered some of the more ridiculous assertions quietly in journals, and continuing his innovative work on lunar and terrestrial meteorite craters and various meteorological phenomena, including how raindrops form in clouds.
Most of these theories are accepted today as scientific truths, yet Wegener's role is often ignored. In 1929, he returned to Greenland to lead a large scientific expedition. He died there not knowing the answer to his real problem: what caused the continents to drift?
After a career in research and education Clare Dudman is a writer and author of Wegener's Jigsaw (Sceptre pound;7.99), a novel based on Alfred Wegener's life.