Plate Tectonic - Plate Tectonics (1) Post Lab
 OBJECTIVES: Comparing the shapes of South America and Africa. Locating South America and Africa on a globe. VOCABULARY: Africa continent South America MATERIALS: worksheet Students examine geographic evidence for plate tectonics. Notice the fit of Africa and South America
 BACKGROUND: The Plate Tectonic Cycle exercises stress the information that earthquakes and volcanoes give us about plate boundaries and plate motions. However, many other types of evidence also support the theory of plate tectonics. One of the first observations used to suggest that the outer portion of the Earth is mobile is the fit of the continents, particularly the west coast of Africa against the east coast of South America. This observation predates plate tectonics. It was first noticed in the 18th century, and most recently proposed by a German scientist, Alfred Wegener in 1912. Wegener called his theory the "continental drift" theory, referring to the apparent movement of continents alone. However, "continental drift" is a historical term that may give the wrong notion to children. We now know it is not the continents that move, but the plates, in which the continents are embedded. South America and Africa were once together, but were split apart by the formation of a diverging plate boundary. This is confirmed by matches between the rocks and fossils of the two continents. Plate motion, not continents drifting, explains this. The two continents are still moving away from each other today. In this handwriting, coloring, and cutting exercise the students will discover that South America fits into Africa, much like a jigsaw puzzle. PROCEDURE: Remind your students that the continents riding on the backs or top parts of the plates. Show them a map of South America and Africa, or use the presentation image below. Ask your students if they believe these two continents were joined together. Hopefully they will see the geometric fit. Remind the class that this is one piece of evidence for plate tectonics. Many other pieces of information were needed to "prove" the theory.    If you have a large world map in your room, go over the different continents with your students and have them try to fit other continents and areas together. If you rotate North America toward the right it fits against Europe. The south coast of Australia fits against Antarctica. India fits between Africa and Australia.   Have the students complete the worksheet. They should trace the names of the continents first, to practice their writing skills. Have them color the continents before they cut them out.