To the teacher: This CPO Science PowerPoint presentation is designed to guide you through the process of presenting the lesson to your students. The presentation uses a 5-E teaching model: Engage, Explore, Explain, Elaborate, and Evaluate. The PowerPoint Slide notes indicate where you may want to bring in various lesson elements such as quizzes, readings, investigations, animations, and practice materials. Additional science background information is provided in the slide notes where appropriate. You can view these notes by selecting “View,” then “Normal.” You will see the notes pane at the bottom of the PowerPoint workspace. Additionally, the slide notes are available as a separate document, accessible from the lesson home page. The slides that follow are intended for classroom use. About the slide notes: The slide notes for this presentation are available in a separate document that you can print and look at while you use the slides. You can access the slide notes document from your teacher lesson home page. Enjoy the lesson!

Why did this mountain explode? On the morning of May 18, 1980, Washington’s Mount St. Helens erupted violently for nine hours. A magnitude 5.1 earthquake kicked off the huge explosion. In just minutes, the 9,677 foot-high mountain collapsed, reduced 1,200 feet by the explosion and a mammoth landslide. So much ash was released that the sky got dark. Mount St. Helens is located along the boundary of two massive tectonic plates. The plates move and shift, creating both volcanoes and earthquakes. ENGAGE: For more facts about the 1980 event, visit http://pubs.usgs.gov/fs/2000/fs036-00/ Assign the student reading prior to the investigation.

Time to investigate! Complete the lesson investigation: Plate Tectonics EXPLORE: Lead the lesson investigation: Plate Tectonics

Divergent plate boundaries Mid-ocean ridges occur where two plates are moving apart. This type of boundary is found over the rising part of a mantle convection cell. As the plates move, molten rock fills the empty space between them. The rock cools and becomes new ocean floor. Rift valleys occur where two continental plates move apart. The East African Rift Valley is a famous example. EXPLAIN: Eventually a rift valley may split wide enough that seawater flows into it. When this happens, the rift valley becomes a mid-ocean ridge. Encourage students to locate the East African Rift Valley on the map on page 2 of the reading.

Convergent plate boundary 1 A deep-ocean trench is a valley on the ocean floor created when an older, denser oceanic plate subducts under a younger, less dense oceanic plate. EXPLAIN: We will look at three cases of converging plates. This slide shows the collision of two oceanic plates. This type of collision forms a deep-ocean trench.

Convergent plate boundary 2 What happens when an oceanic plate collides with a continental plate? The denser oceanic plate subducts under the continental plate. The Andes Mountains, pictured here, formed as the subducting oceanic plate deformed and pushed up the land at the edge of the continental plate. EXPLAIN: Students should know that the collision of an oceanic and a continental plate can cause mountains to form.

Convergent plate boundary 3 When two continents collide, mountains form! The Himalaya Mountains are the result of the collision between India on the Indo-Australian Plate and China on the Eurasian Plate. EXPLAIN: The Indo-Australian oceanic plate carried the landmass of India toward China as it subducted under the Eurasian continental plate. When all of the oceanic crust was subducted, the two continental plates collided. Continental plates are less dense than oceanic plates, and too buoyant to be subducted into the trench. The collision between the two continental plates forms mountains and causes earthquakes.

Transform fault boundary A transform fault boundary occurs where two plates slide by each other. Offsetting occurs when a feature like a creek or road crosses a transform fault. The movement of the fault will break, or offset the feature, causing a zig-zag appearance. Earthquakes sometimes occur at transform fault boundaries. EXPLAIN: Students should know that earthquakes occur at all three types of plate boundaries. However, while volcanic activity occurs at diverging and converging boundaries, it is not a common feature of transform fault boundaries. Assign the plate tectonics video for review. It can be accessed from the multimedia lesson home page.

Time for Practice! Complete the lesson practice activity: Continental United States Geology As you read this activity sheet, make a list of major land features of the United States and identify which types of plate movements were involved in their formation. ELABORATE: This practice sheet provides an opportunity for students to relate plate tectonics to the formation of crustal features found in the continental United States.

Show what you know! Try the lesson’s interactive quiz, or complete a quiz that your teacher can print out for you. Hint: You might want to review your lesson reading piece one more time before trying the quiz. EVALUATE: Print out the 10-question quiz for students to complete, or have students work individually at computers to complete the interactive quiz they can access from the multimedia lesson home page.