Transcript External Forces of Change

External Forces of
Change
Weathering & Erosion
1. Bryce Canyon, Utah
2. Grand Canyon, Arizona
3. Glacier National Park,
Montana
4. Bronze turning green when exposed to
elements
5. Broken tombstone
6. Mammoth Cave, Kentucky
7. Grand Tetons, Wyoming
8. Trees atop Mt. Mitchell, North
Carolina
9. Capital Gorge, Utah
10. The Great Lakes – NE U.S.
1. Bryce Canyon, Utah
wind and little water erosion
2. Grand Canyon, Arizona
water erosion
3. Glacier National Park,
Montana
4. Bronze turning green when exposed to
elements
chemical weathering – acid rain
5. Broken tombstone
physical weathering
6. Mammoth Cave, Kentucky
chemical weathering (carbonic acid)
7. Grand Tetons, Wyoming
glacial erosion
8. Trees atop Mt. Mitchell, North
Carolina
chemical weathering (acid rain)
9. Capital Gorge, Utah
wind and water erosion
10. The
Great Lakes – NE U.S.
glacial erosion
1. Explain the difference b/w weathering
& erosion.
 Weathering
breaks down rocks on
Earth’s surface into smaller
pieces
 Erosion wears away Earth’s
surface (wind, glaciers, moving
water)
2. Explain the difference b/w physical
& chemical weathering; give example.
 Physical-
breaks rock into smaller
pieces

Water freezes in crack, ice splits
rock
2. Explain the difference b/w physical
& chemical weathering; give example.
 Chemical-
changes the actual
chemical make-up of the rock

Water + CO2 destruction of
limestone
3. What causes acid rain?
 Acidic
chemicals from pollution
(factories, etc) combine w/
precipitation

Eats away at buildings, kills
fish/plants, etc.
4. What is wind erosion?
5. Benefits & drawbacks?
 Movement
of dust, sand, soil from
one place to another
Benefits: Mineral-rich soil is
deposited creating fertile soil
 Drawbacks: Good soil can be
carried away leaving land barren

6. Define LOESS.
 Fertile,
yellow-gray soil carried
by wind throughout the Yellow
River leaving the land great for
farming
7. How can glaciers cause erosion?
 Slowly
move
downhill p.u.
soil/rocks destroy
forests, carve
valleys, alter river
course, wear down
mtns.
8. What are moraines?
 Large
piles of debris/rocks left
behind by glaciers

Form long ridges of land or create
dams that form glacial lakes
9. Describe the difference b/w sheet
glaciers and mtn. glaciers.
 Sheet:
flat, broad
sheets of ice
(Greenland,
Antarctica)

Can break
off to form icebergs
 Mtn:
found in
high mts.
(Rockies)

Move
downhill
creating
valleys
10. How does water cause erosion?
 Fast-moving
water
 cuts into land,
wears away
soil/rock  creates
sediment which
grinds away other
rocks
 Waves erode cliffs,
beaches, etc.