Plate Tectonic - Plate Tectonics (K)
Post Lab 

  • Comparing the continents with plate boundaries.
  • Locating continents on a world map.
  • continents
  • plate

Students compare continents with plates.


The surface of the Earth seems to be divided into water and land. Islands look disconnected, and many children even think that they are floating on the water. Many books describe plate tectonics as if the plates are the continents. This is not true. The continents are embedded in the plates. Many continents occur in the middles of plates, not at their boundaries or edges. Plates also underlie the Earth’s oceans. A single plate often includes both continental and oceanic regions. It is important that students begin to visualize or understand that the plates are a solid rock shell which includes both dry land and the "land" underneath the oceans.

Plates are composed of the Earth’s crust and upper mantle, which are collectively called the lithosphere. This layer is like an eggshell compared to the total thickness of the Earth. Plates do not extend all the way to the center or the Earth.

All of the plates are moving. They are slow, moving at speeds of centimeters to tens of centimeters per year. They slide along on top of an underlying mantle layer called the asthenosphere, which contains a little magma (molten rock).

The plates are layers of rigid, solid rock. However, as they move, plates interact at their edges or boundaries. There are three basic directions or types of boundary interactions. In some places, two plates move apart from each other; this is called a diverging plate boundary. Elsewhere two plate move together; this is a converging plate boundary. Finally plates can also slide past each other horizontally. This is called a transform plate boundary. Volcanoes and earthquakes help define the boundaries between the plates. Volcanoes form mostly at converging and diverging plate boundaries, where much magma is generated. Earthquakes occur at all three types of boundaries. Because the plates are rigid, they tend to stick together, even though they are constantly moving. When the strength of the rocks at the plate boundary is exceeded, they move rapidly, "catching up" with the rest of the plates. We feel this release of energy as an earthquake.


  1. The key concept for the Post Lab is to make sure that the students do not confuse the continents with the plates. The continents are part of the plates. Point out the continents to the class on a world map. Have the students repeat the names of the continents. Keep repeating to them that the continents have moved by riding on the backs (or tops) of plates for millions and millions of years.

  1. Ask the students if any of the continents look like they might have been attached. Hopefully they can see that the fit between South America and Africa is very good.
  2. Read Look Inside the Earth to the class. There is not much of a story in this book, but the pictures are useful for guiding a classroom discussion. This book peels away the Earth's layers in a way which may help children to visualize the inside of the Earth. Remember to emphasize that the plates are composed of the crust and upper mantle. The students will love to touch and play with this book.

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