Presentation on theme: "Mr. Burton 2.3 Notes Please Grab: 1. Your folder. 2. Writing Utensil. 3. Answer the following question: How does the surface of the earth move?"— Presentation transcript:
Mr. Burton 2.3 Notes Please Grab: 1. Your folder. 2. Writing Utensil. 3. Answer the following question: How does the surface of the earth move?
Earth’s surface has many different landforms Landforms, or shapes on the planet’s surface, make up the landscapes that surround us. Earth’s surface is covered with landforms of many different shapes and sizes. Mountains, land that rises higher than 2,000 feet Valleys, areas of low land located between mountains or hills Plains, stretches of mostly flat land Islands, areas of land completely surrounded by water Peninsulas, land surrounded by water on three sides
Below the earth’s surface The planet’s continents, or large landmasses, are part of Earth’s crust—the solid outer layer of the planet. Theory of plate tectonics suggests that Earth’s surface is divided into a dozen or so slow-moving plates, or pieces of Earth’s crust. The idea that continents have traveled great distances over millions of years is known as continental drift. Theory, developed by Alfred Wegener, states that the continents were once united in a single supercontinent and over time, slowly separated and moved to their present positions. As plates collide, separate, and slide, they shape Earth’s landforms
Collide, Separate, and Slide Two ocean plates: one pushes under the other, creating ocean trenches, or deep valleys in ocean floor Ocean and continental plate: ocean plate drops beneath continental plate, forcing land above to crumple and form mountain range Two continental plates: land pushes up to form mountains As plates move apart, gaps between plates allow magma to rise to Earth’s crust. Lava, magma that reaches the Earth’s surface, emerges from the gap. As lava cools, it builds a mid-ocean range, or underwater mountain, that can rise above the surface of the ocean to form islands. As plates pass by each other, they sometimes grind together, producing earthquakes, sudden, violent movements of Earth’s crust. Earthquakes often take place along faults, or breaks in Earth’s crust where movement occurs. The region around the Pacific plate, called the Ring of Fire, is home to most of the world’s earthquakes and volcanoes.
Forces on the planet can alter the earth’s surface. Weather, water, and other forces change Earth’s landforms by wearing them away or reshaping them. Weathering is the process by which rock is broken down into smaller pieces called sediment. Heating and cooling can cause rocks to crack. Expansion of water as it freezes can cause cracks to expand. Roots of trees can pry rocks apart. Erosion is the movement of sediment from one location to another. Can wear away or build up landforms
Different types of erosion: Wind, Glacial, and Water Winds lift sediment into air and carry it across great distances. On beaches and in deserts, deposits can form dunes. Blowing sand can wear down rock. Glaciers, or large, slow-moving sheets of ice, erode the land by carving valleys and mountain peaks. Crush rock into sediment and move it great distances Waves and flowing water can cut through rock, carry sediment, and deposit sediment in new locations. Floodplains are created when rivers flood their banks and deposit sediment. Sediment carried by a river all the way to the sea creates a delta.
Exit Slip: What are the three types of erosion that we have?