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Quick overview for class unit on erosion and natural resources
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What are natural resources? • Anything that exists in nature and is not made by man. • Examples include water, forests, air, and land.
Can you name some other things in nature that are not made by man?
Types of Resources Renewable Can be used over and over Naturally replaced at a rate where we are not at risk of using up the supply Non Renewable Cannot be naturally replaced as fast as they used.
Weathering and Erosion • Grab your pencil and erase with it. How does this affect your eraser? http://studyjams.scholastic.com/studyjams/jams/science/rocks-minerals-landforms/weathering-and-erosion.htm
Let’s Review! • Weathering –breakdown of material in Earth’s crust into sediment • Erosion – weathered rock is carried away by gravity, water, wind, and ice • Physical weathering- process of erosion that physically changes composition • Chemical weathering- process of erosion that affects the chemical composition usually caused by acid rain • Sediments- broken down materials deposited by wind or water
Causes of Erosion • Wind • Water • Chemicals • Humans
Wind Erosion biocircuits.ucsd.edu Image link
How long do you think it takes to form something like the Grand Canyon with water erosion?
Chemical Erosion sciencing.com Image credit
What are some ways you have seen humans in your area contribute to erosion?
Focus on Human Impact Deforestation Removing large sections of forests expose land to elements. Agriculture • Plowing fields softens top layer of soil making it easier to be moved by rain or wind.
Terracing permaculturenews.org