Erosion is the transportation of weathered materials by wind, water, ice, or gravity. Water and ice erode rocks by entering cracks and expanding when freezing, weakening the rock over time. Erosion causes mudslides and landslides when materials slide down hills. Deposition occurs when sediment is deposited by slowing winds or water in places like river deltas or banks. Weathering breaks rocks into smaller pieces through extreme heat and cold, water, and ice wearing away at the rocks. There are three types of weathering: mechanical, physical, and chemical.

1. Deposition, Erosion, and WeatheringBy: Jennifer, Savannah, Alyssa, and XavierThis is a student Web page. Opinions expressed on this page shall not be attributed to San Antonio ISD

2. ErosionErosion is simply the transportation of weathered, or broken down, materials. Wind and water can erode, and so can movements from the earth. Water can carry the broken down rocks, and so can wind. A landslide is when lots of materials are carried down a steep hill by gravity.

3. The causes of erosion are by wind, water, and ice. Water and ice erode rocks for example when it rains water gets into little cracks that naturally occur in rocks, when it gets cold water freezes and expands, after this cycle is repeated a couple of dozen times the rock gradually becomes weaker and cracks .Effects of ErosionMudslides occur when erosion is taking place on a hill or other places. A mudslide is when water makes the side of a hill heavy, and carries it downward. Slumps are when a large amount of rock or dirt, or other sediments, fall. All the material in a slump always comes down at once, where a landslide can have many rocks tumbling down at different times. When the earth moves slowly, it's called a creep. This is a picture if a mudslide

4. Causes of DepositionDeposition is when sediment, and broken down substances are deposited, or laid down somewhere. This can happen in a river when the water slows and creates a new bank, or delta. When wind slows down it can also drop sediment. Effects of DepositionDeltas form wherever rivers encounter standing bodies of water such as lakes or oceans. The sudden decrease in energy causes the river to drop the sediment. Whether river deltas become swamped by rising sea levels will depend on a multitude of factors, including the type of soil and the tectonic action of any nearby plates.

5. WeatheringWeathering is where rocks and minerals are broken down into smaller and smaller pieces. Extreme heat and cold, water, and ice can all cause weathering. Water wears away rocks, and can dissolve them. When water seeps into cracks on a rock, it freezes, and gets bigger, causing the rock to push out.Types of Weathering There are three types of weathering and they are know as mechanical, physical, and chemical weathering.Chemical weathering occurs at a faster rate when the temperature increases, and when a rock opens that’s when all the chemical reaction occurs.Mechanical weathering occurs when the temperature is cold. It opens up cracks and the water that is let in attacks the minerals and make the rock break into smaller particles. Physical weathering occurs when the parent rock into bits and pieces by exposure to temperature changes and the physical action of moving ice and water, growing roots, and human activities such as farming and construction.Left picture is of physical weathering, right picture is of chemical weathering and the bottom picture is of mechanical weathering.

6. Resourceshttp://gsc.nrcan.gc.ca/landscapes/details_e.php?photoID=547

7. http://www.uh.edu/~jbutler/physical/weathering1.gif

8. http://www.google.com/search?hl=en&source=hp&q=deltas&aq=f&oq=&aqi=g10

9. http://www.angelfire.com/squirmy_the_wormy/.html