Weathering and Erosion

• weathering-slow process that breaks down rock into smaller pieces (water, rain, wind)
• physical weathering-rocks change size and shape, but not type or rock (chemical makeup)
• flowing water makes rocks smooth

 

• freezing and melting water can split rocks apart
• plant roots can break rock

 

• chemical weathering-changes what rocks are made of (oxygen, CO2, acid)
• lichens (like mosses) can soften rocks
• transport (moving) or weathered rock is erosion
• flowing water, rainwater, waves, wind, gravity all cause erosion (carry rock to a new place)
• deposition-dropping off of weathered rock in a new place
• glaciers-large masses of ice and snow

 

• bottom of glacier freezes to rocks, tears them apart as it moves (can make valleys and scratches in rocks)
• glaciers leave debris (leftover rocks) can be large or small
• the glacier leaves most rocks at the end of it's downhill, or terminus
• a mix of glacial debris (rocks, pebbles, gravel, sand, clay) is called glacial till
• glaciers form hills called moraines
• people can change the land by mining (taking minerals or resources out of the land)

 

• landfill-place where people pile trash
• people cut down forests to make lumber (build homes and furniture) and paper