Unit 2 Notes: Weathering and Erosion Remember to highlight all bold words, underline all definitions, and don’t forget to copy all titles!

Weathering Definition  The breaking of rock 2 Types of Weathering 1. Mechanical Weathering Definition When a rock is physically broken into smaller and smaller pieces of the same type of rock (NO changing) Mechanical weathering happens from several agents that happen in natures

Examples of Mechanical Weathering Frost wedging When water gets into the cracks of rocks, it freezes and since ice expands, it will open the crack even further Water Each little bit of moving water will knock off pieces of rock, where a small sediment will knock off another and another would knock off even more

Examples of Mechanical Weathering Humans Through everyday processes like construction, farming, and other movements of soil Wind  Sand blasting on rocks is using sediments that are blown around by strong winds to break even more rocks off (think fire hose with sand instead of water)

Types of Weathering 2. Chemical Weathering Definition  When a rocks is broken into smaller and smaller pieces, but through chemical reactions and solutions that mix in nature Water is the most common chemical weathering agent because it creates perfect conditions for a chemical reaction Warm temperatures also create perfect conditions for chemical weathering What type of biome would have the most chemical weathering? Rainforest because of high amounts of water and warmer temperatures

The rock’s characteristics and the minerals that are found in a rock are going to determine the rate at which a rock will weather.

Erosion Definition  The movement of sediments from one place to another

Agents of Erosion 1. Gravity If a rock is broken off something, gravity is the force that is moving it then. Gravity will move the largest of sediments because all objects on Earth are subject to gravity pulling towards the center of the Earth Strongest force to move sediments Landforms that are made when gravity pulls a rock off would be cliffs

Agents of Erosion continued 2. Ice When large sections of ice called glaciers move across the land, the rocks that they move over will be picked up by the ice and carried as the ice moves Ice will pick up the larger sediments and move them hundreds to thousands of mile Second strongest force to move sediments Landforms that are made from these glaciers of ice moving the sediments are sharp mountains and deep valleys

Four Agents of Erosion 3. Water  Most common of the agents of erosion, water moves sediment on Earth than anything else Most sediment is moved by water in lakes, rivers, and streams Third strongest force to move sediment Landforms that will be made from this movement of sediments will be mountains into hills and valleys

Agents of Erosion continued 4. Wind Will pick up many small sediments, but there is not a high enough velocity of wind that will pick up large boulders Winds that will pick up larger sediments would be found in sandstorms and hurricanes Fourth strongest force to pick up and move sediment Landforms that are made from wind moving sediments will things like sand dunes

Sometimes, humans are considered erosional agents because of all of the construction that occurs all over the planet. In this case, an erosional agent has to be a force of natural origins. >Erosion rates on Earth have increased with the active storms and high energy hurricanes/tornados that have been getting large due to increased temperatures from global warming