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W eathering, E rosion, and D eposition (pg 299). WED. Weathering. Weathering . Weathering is the physical or chemical process that breaks down rock on or near Earth ’ s surface. Weathering is a slow process. In fact, it can take millions of years to weather an exposed rock layer.
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Weathering • Weathering is the physical or chemical process that breaks down rock on or near Earth’s surface. • Weathering is a slow process. In fact, it can take millions of years to weather an exposed rock layer. • Sediment is the small particles of rock, soil, sand or shell that is broken away due to weathering.
Two kinds of weathering: Physical weathering: Chemical weathering: Occurs when chemical reactions cause rocks to weaken or wear away. Dropping acids on rock will cause the rocks to dissolve. • Occurs when a mechanical process breaks down rocks. • Ex: Breaking a rock with a hammer. Water can also cause physical weathering.
Agents of weathering: • The agents, or causes, of weathering are: • Wind, Water, Ice, Heat!
Erosion • Erosion is the movement of weathered rocks and soil. • Pieces of Earth’s crust are picked up and carried away. • Agents of erosion are wind, flowing water, waves, and gravity.
Deposition • Deposition occurs when an agent of erosion drops, or deposits, its load of sediment in a new place. • Deposition slowly builds up the surface and changes Earth daily.
Sedimentary rock (pg 308) • Sedimentary rock is made of sediment. These rocks can form when existing rock is weathered, eroded, and deposited in layers on land or underwater.
Questions! • Use your textbook to answer the following questions in your science journal. • How does ice cause weathering? (pg 302) • How does deposition create a delta? (pg 307) • How is sedimentary rock formed? (pg 308) • How is rock salt and gypsum formed? (pg 309)