That's right. That great big continent that's under your feet slides around the planet like a big graham cracker. Look at a map in your classroom. The seven big blocks of land called continents are moving through the sea a little bit every day. How does this happen? Who figured this out? If they're moving, where did they start from? And where will they end up?
Can you feel the earth move under your feet? No, of course you can't. A man named Alfred Wegener
(1880-1930) also did not feel the earth move under his feet, which makes it even more impressive that he figured out that the continents move! He began his career studying stars, then moved on to rocks, and finally weather. He was interested in everything, which is never a bad thing. Reading in a library one day, Alfred came across a list of the same animals that live on the shores of both America and Africa. How could the same creatures live on lands separated by the ocean? At the time, people believed that there had been bridges of land connecting these coasts and that these bridges had sunk beneath the waves. Wegener kept searching for a better answer, though. Then he noticed something big. The coasts of the two continents looked like they fit together like two puzzle pieces . . .
Hey, where are you going?
If you take a copy of a map and cut out the shapes of the continents, you will be able to fit them all together. Of course, over hundreds of millions of years, the land has curved and lost little pieces of land as islands, so it will not be a perfect fit. With a little bending, though, you can make it work. Others had noticed that the coasts seemed to fit, but Wegener had a leg up on them. Thanks to his study of weather and rocks, he was able to find evidence to support his ideas. He found that not only did the continents fit but also saw that the same plants, broken mountains, and even the lines in the rocks matched up too. This helped him come up with the fit of the continents
, which is the idea that all the continents must have all been touching at one point. Over time, the land must have separated and drifted apart, taking the living things on them along too.
What does this mean? It meant that all animals, plants, and everything we can see came from the same big piece of land. It's only when that land broke up and floated apart that the animals started to change and look a lot different. Pangea
is the name Wegener gave to the great piece of land that held all of the continents together as one. The name means "all the land." He came up with the idea that one hundred and thirty million years ago, it broke apart like the graham cracker in milk. This idea was so big and so different that no one believed him.
One big happy family.
It was not until after Wegener died seventy years ago that people saw that he was right. When scientists studied the earth's crust, they found it was made up of giant plates. The continents are all part of pieces of earth, which are 80 to 400 miles thick. Wegener called his idea continental drift
, which meant that our land slowly drifts like pieces of wood across the ocean. He got this one wrong. The land is connected to the ocean floor, which is also a part of the plates that are moving. Instead of water, these plates slide around on top of the earth. It's a surface of cool rock that sits on rock that's so hot that it becomes slippery like butter . . . or more like lava.
Some things in our world happen so slowly. It's hard to see that they are happening at all. Wegener used his curiosity and his experience with rocks and weather to figure out that the continents had fit together at one point but had been slowly drifting apart for millions of years. This gives us the answer to so many questions. How can the same animals come to live on two different coasts that have a huge ocean between them? Stay curious and keep your eyes open. Who knows what you may find?
Enchanted Learning. "Continental Drift." Enchanted Learning, 1996. <http://www.enchantedlearning.com/subjects/dinosaurs/glossary/Contdrift.shtml>
UCMP. "Alfred Wegener." UCMP, 2010. <http://www.ucmp.berkeley.edu/history/wegener.html>
How Stuff Works Videos. "100 Greatest Discoveries: Continental Drift." Discovery, 2011. <http://videos.howstuffworks.com/science-channel/29267-100-greatest-discoveries-continental-drift-vid...
Scientus. "Wegener and Continental Drift Theory." Scientus, 2014. <http://www.scientus.org/Wegener-Continental-Drift.html>