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Earth’s LandLandforms are shapes on the planet’s surface (mountains, valleys, plains,
islands, hills, peninsulas, etc.)Mountains are over 2,000 feet in
elevation.
Plate Tectonics
The Earth’s surface is divided up into large sections called plates.
Plate tectonics theory states that the Earth’s surface is divided up into a dozen or so slow moving plates. Continents are located along these plates along with the ocean floor.
Plate Tectonics
Earth’s plates sometimes collide, slide, or separate from each other.
The German scientist, Alfred Wegener, developed the continental drift theory; which states all the continents were once part of a single supercontinent.
Plate Tectonics Continued
When plates collide, either mountain rages or ocean trenches are formed.
When plates separate, lava often is released through the Earth’s crust, thus forming mid-ocean ridges or underwater mountains (ex. Iceland).
When plates slide past each other, earthquakes can occur (fault lines).
Forces on Earth’s Surface
Weathering is the process by which rock is broken down into smaller pieces.
Erosion is the movement of sediment from one location to another. Wind, ice, and water all cause erosion.
Lesson Visuals
Page 36 – Earth’s Plates.
Page 38 – Plate Movement.
Page 39 – Wind Erosion.
Page 40 – Water Erosion.
Page 41 – Living With Landforms.
Pages 42/43 – Ring Of Fire, Chart, Mount St. Helens.
