1. Weathering, Erosion, and Deposition
Notes

2. Weathering – the process by which rocks are broken down into sediments slowly over time
Mechanical weathering
breaks down rocks into smaller pieces through physical processes
changes the shape and size of a rock, but it doesn't change the rock's chemical composition
Wind*, water*, living things, changing temperatures all cause weathering.
Chemical weathering
breaks down rocks through chemical processes
changes the rocks' chemical composition

3. Erosion
moves sediments to other locations
Flowing water* can carry rocks, sediments, and soil downstream
Wind* is another agent of erosion
Animals are agents of erosion as they burrow into the ground, moving sediments out of their way
Another erosional agent is gravity, which constantly pulls rocks downhill as they weather

4. Deposition
When sediments stop moving and settle where the erosional agents have carried them (from the word “deposit”)
When sediments are eroded by wind, flowing water, ice, or gravity, they are generally deposited in horizontal layers

5. Human activities cause weathering and erosion:
Digging and moving soil during construction
Cutting down trees – soil is less stable and more vulnerable to erosion
Pollution – adds more chemicals to the air  acid rain