Plate Tectonic - Plate Tectonics (K)
Pre Lab 

   
OBJECTIVES:
  • Exploring the movement of the outer portion of the Earth.
  • Introducing plate tectonics.
VOCABULARY:
  • continent
  • crust
  • movement
  • plate tectonics
  •  
MATERIALS:

Students complete a puzzle illustrating plate tectonics


A map of the plates

BACKGROUND:

Understanding the movement and behavior of the Earth's outermost layers has been a painstakingly long scientific process. The theory of plate tectonics is our current "best explanation" and working model. Plate tectonic theory has developed slowly and progressively since it was developed in the 1960s. It is a theory that truly has the entire world as its experiment.

According to the theory of plate tectonics, the Earth's crust and upper mantle are broken into moving plates of "lithosphere." The Earth has two types of crust. Continental crust underlies much of the Earth’s land surface. The ocean floors are underlain by oceanic crust. These material have different compositions. The continental crust is lighter, similar to granite, and the oceanic crust is denser like basalt, another igneous rock. Continental and oceanic crust can both be part of the same plate. For example, the North American plate has continental crust (essentially the land area of North America) at its core; this is surrounded on most sides by oceanic crust. A geographic "continent" does not equal a plate.

The lithospheric plates are solid rock. There are several very large plates, each consisting of both oceanic and continental portions. There are a dozen or more smaller plates. The plates average about 80 kilometers (50 miles) in thickness.

PROCEDURE:

  1. Introduce the phrase "plate tectonics" to the class. Explain that it describes the movement of the Earth's outer portion (the crust and upper mantle). Illustrate the crust of the earth by using a globe or an orange (the peel is the crust and the fruit inside is the rest of the Earth.)
      
  2. Show the students a globe. Point out the continents on the Earth's surface. Explain that scientists have evidence that the continents have moved great distances during the course of the Earth's history. Ask the students this question: if one continent broke up and moved apart, would the pieces resemble one another and fit together? They may answer yes or no. Both answers are actually correct; sometimes split continents still match up, i.e., South America and Africa. In other cases, such as Europe, Greenland, and North America, the match-up is very obscure.  
      
  3. To understand plate tectonics, students must be familiar with the globe. Point out the continents and the oceans by making the class repeat the names of the continents. Explain that the continents are merely the crust exposed above sea level, and that the solid surface of the Earth below sea level is also crust. Tell the class that the crust is broken into pieces which are called "plates." The continents are the exposed portions of the Earth's plates. However, some continents may be composed of the exposed sections of more than one plate. Therefore "continent" does not equal a plate. This may be a confusing point for adults and children alike.
     
  4. Have the students complete the worksheet. Instruct them to color Moppy and Moppa, the continents, and the oceans. When they have finished coloring they should cut Moppy and Moppa out and fit them together once again. You can create a story about Moppy and Moppa being together on a continent that was riding on a single plate. The plate broke apart when they had a fight. Now Moppy and Moppa have made up and want the plate to come together again.
      
  5. Have the students observe that the edges of the plates fit. Make sure they see that there is only one part of the plate on which Moppy and Moppy can meet (the continent).

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