JH+Earth+Processes

What is Tectonism? Click [|here] to find out.
 * Plate Tectonics **



On the Alfred Wegner slide the phrase Ma is used. It stands for megannum which is "millions of years ago". If you ever see Ga, it's gigannum which is "billions of years ago".

Earthquakes occur at the mid-ocean ridge because of the transform boundaries that are there. Look again at the Tuzo Wilson slide. There are "breaks in the mid-ocean ridge where the boundary is actually a transform boundary rather than a divergent boundary. What type of event is likely to occur at a transform boundary? Earthquakes!



The Activities 1, 2, and 3 mentioned in the Plate Tectonics PowerPoint are from a lab called Discovering Plate Boundaries (DPB). It is a fabulous ** inductive ** learning activity. Students study maps and make observations. Then they share those observations about the maps and draw conclusions about what is happening at plate boundaries.

It will take a teacher some time to decide how to use it in class and it will take at least 3 days for the activity. A modification would be to show the maps to the class, make observations and draw conclusions together.

Even if you don't use this activity, use the maps. The are clear and easy-to-read. Click [|here] for DPB QuickStart Click [|here] for DPB Teachers Guide Click [|here] for DPB Maps and Student Guides

How fast do plates move? That might be a question that you are asked by your students. The attached Hot Spot Activity is a way for students to find out. One potential modification for this activity is to make a human graph with the information. Mark the X and Y-axis on the floor and have students plot the points. Then use a long string to help determine the line of best fit for the graph.

What Happens at Plate Boundaries?

**Layers of the Earth**

View the Layers of the Earth PowerPoint to understand the basics about the layers of the Earth. (Technical Note: the presentation should include 6 slides total. If you can't view all 6 slides, save the presentation and then view it.) So, the Earth has 3 compositional layers (the core, mantle, and crust). In addition, there are 3 layers that are idenitified by their mechanical properties (strength): the lithosphere, the asthenosphere, and the mesosphere.
 * __Lithosphere__**
 * The Plates in Plate Tectonics
 * Upper 100 km
 * Crust and upper mantle
 * Rigid


 * __Asthenosphere__**
 * 100 km to 300 km?
 * Upper mantle
 * New melting point; little strength; ductile-NOT a liquid
 * Plates moving on this layer
 * Source of magma


 * __Mesosphere__**
 * Extends to core
 * Also hot; strong due to pressure

Both the mantle and asthenosphere are hot enough to be molten but both layers are under so much pressure that they are not molten.



How do scientists know about the interior of the Earth? They use clues gathered through seismic waves.

This would be a great way to talk to students about theories. Create a **Mystery Balloon** exercise where you fill ballons with different materials and have students draw conclusions about what is in the balloons. Then lead students to talk about how they came to thier conclusions and if thier data is reliable. Relate the activity to how scientists are fairly certain about the specifics of Earth's interior even though no one can travel there. Balloon Suggestions: some with water, beads, nuts, small pieces of straw, etc.

Modeling the Magnetic Field Put a cow magnet through a styrofoam ball. Roll the ball through "stapled" staples to create a magnetic field. You can also use this activity when talking to students about the evidence for plate tectonics. If you line up the staples end to end students should be able to see how the rock layers line up the magnetic poles.

Igneous Rocks
 * Rock Types **

Sedimentary Rocks

Metamorphic Rocks

**Volcanoes and Earthquakes**

Click [|here] for a brief description of volcanism.


 * Types of Volcanoes**
 * 1) Cinder Cone
 * 2) Shield
 * 3) Composite

Click [|here] for a brief description and pictures of each type of volcano.

The following activity will have students draw conclusions about the type of igneous rocks that are found at boundaries and how that relates to the type of boundary it is and what activities occur at those boundary types. Students will need to know about igneous rocks--how the composition of the rock affects what type of rock it is, its mass, color, etc.
 * 1) Materials: the Volcano Data Table, a world map with latitude and longitude lines, colored pencils.
 * 2) Assign the rock types a color (Ex. Andesite = Green, Rhyolite = Red, Basalt = Blue). Then have students plot colored points on thier map that corresponds to the data table.
 * 3) Then ask students to draw conclusions about the relationship between the type of boundaries the volcanoes are found at and the type of rock found there. Why is basalt found at divergent boundaries? Why are andesite and rhyolite found at convergent boundaries?


 * Types of Lava**

View the Volcanism PowerPoint about different types of lava and where it forms. Some possible activities for demonstrating lava types are: Cake Batter Lava and Mentos Volcanic Explosions.

Making and Mapping a Volcano is an activity designed to have students observe lava flow and understand how it affects topography.