weathering and erosion

weathering takes time

No human being can watch for millions of years as mountains are built, nor can anyone watch as those same mountains gradually are worn away. But imagine a new sidewalk or road. The new road is smooth and even. Over hundreds of years, it will completely disappear, but what happens over one year? What changes would you see? (Figure 1.1). What forces of weathering wear down that road, or rocks or mountains over time? A once smooth road surface has cracks and fractures, plus a large pothole. Click image to the left or use the URL below. URL:

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weathering

Weathering is the process that changes solid rock into sediments. Sediments were described in the chapter "Ma- terials of Earths Crust." With weathering, rock is disintegrated. It breaks into pieces. Once these sediments are separated from the rocks, erosion is the process that moves the sediments. While plate tectonics forces work to build huge mountains and other landscapes, the forces of weathering gradually wear those rocks and landscapes away. Together with erosion, tall mountains turn into hills and even plains. The Appalachian Mountains along the east coast of North America were once as tall as the Himalayas.

instructional diagrams

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questions

the process that changes solid rock into sediments.

a) erosion

-->  b) weathering

c) dissolution

d) fracture

the process that moves sediments.

-->  a) erosion

b) weathering

c) dissolution

d) fracture

weathering happens rapidly; often in a matter of years or decades.

a) true

-->  b) false

the appalachians were once as tall as the himalayas and have since weathered and eroded.

-->  a) true

b) false

what can cause erosion?

a) water

b) wind

c) ice

-->  d) all of the above

which is an example of chemical weathering?

a) a rock breaking into fragments.

b) a rock being scratched by rocks embedded in the bottom of a glacier.

-->  c) a rock dissolving in water.

d) sediment being moved down a hillside.

weathering and erosion can change land over time.

-->  a) true

b) false

weathering can change roads, sidewalks, buildings and sculptures over time.

-->  a) true

b) false

the gargoyles on notre dame cathedral are pitted in ways the artists never meant to happen. this is due to

-->  a) chemical weathering

b) mechanical weathering

c) erosion

d) all of the above

if a river in flood picks up a house and moves it downstream, this is

a) chemical weathering

b) mechanical weathering

-->  c) erosion

d) all of the above

diagram questions

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