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Forces that Change
Earth’s Surface
I-Interacting Earth Systems:
A-Three spheres of the earth:
1- Lithosphere = rock or land
2- Hydrosphere = water
3- Atmosphere = gases
4- The exchange of energy between the
three spheres cause changes in the
Earth’s surface.
B- External Forces: wear the
land down to sea level.
1- Weathering breaking down of
rocks into smaller pieces.
a- ice, rain, and gases.
2- Types of Weathering:
a- Physical weathering:
~Frost Action:
repeated
freezing and
melting
{Glaciers}
Water seeps
into cracks
and expands
when it
freezes
breaking
rock apart
~Root-pry:
roots grow
between
cracks and
grow causing
rocks to break
apart.
~Gravity: pulls
loosen rocks & soil
down. {Landslide}
~Abrasion: wind
& water carry
solid particles
that sand down
rock.
b- Chemical weathering:
changes occur in the mineral
composition or chemical
makeup of rock.
~Water: dissolves soluble rock
~Oxidation: Oxygen combines
with another substance to form
a new material.
~Carbonation: A weak acid is
formed when carbon dioxide
dissolves in water called
carbonic acid which dissolves
rock.
~Sulfuric acid: Acid Rain When
sulfurous gases combines with
water. Wears away rock and
other materials very quickly.
a- Mountains produced mainly by
folding and faulting.
~Folding takes place when the
crust presses rock causing it to
bend.
C- Internal Forces: Forces that
produce mountains,
earthquakes, & volcanoes.
1-Mountains, Plains, & Plateaus
~Faulting occurs when forces in the
crust squeezes or pull causing it to
crack or break along a fault = stress
in crust.
~Mountains can also be formed by
volcanoes: Lava pours out cools pours
out cools forming layers of igneous
rock.
b- Plains: are broad, flat regions found
at low elevation. Made of sedimentary
rock layers underwater that have
slowly raised.
c- Plateaus: Large area of flattopped rocks, caused by faulting or
lava flows.
D- Earthquakes: Sudden
movements of rocks
sliding along faults in the
crust. Earthquakes cause
strong vibrations that
travel through the Earth.
1- Three Types of Waves:
a- Primary waves (P-waves) can
travel through liquids and solids.
b- Secondary waves (S-waves)
travel only through solids.
c- Longitudinal waves (L-waves)
surface waves.
E- Structure of Earth:
1- Crust: Outer layer of Earth.
Composed of solid rock
material about 8-32 km
thick.
a- Moho: between the crust
and Mantle
2- Mantle: Below the crust about
2900 km thick consisting of iron
and magnesium.
3- Outer Core: Below the mantle
about 2300 km thick liquid.
{S-waves cannot go through it}
4- Inner Core: Solid material
about 1200 km {P-waves travel
faster through it}
F- Continental Drift: was proposed by
Alfred Wegener in 1912, based on the
continents fitting together like a puzzle
known as Pangea {pan-jee-uh}
1-Wegener also
based his theory
of fossils, rocks,
mountains, and
glacial features
found on both
sides of the
Atlantic.
G- Seafloor Spreading
Oceanographers discovered an
underwater mountain ridge running
north-south down the middle of the
Atlantic Ocean (Mid-Atlantic Ridge).
Along the ridge, there was volcanic
activity. This building of new rock which
moves east and west supports Wegener
theory.
H- The Theory of Plate Tectonics is
the combination of continental drift
and ocean floor spreading.
1- According to the theory the
Earth’s crust is broken up into
large plates that move an interact.
2- Scientist believe the plates move
due to the heat is the mantle
circulating.
Mapping the world
A-Latitude- The Earth is a
sphere if you cut it horizontally
or vertically into circles.
1.The distance between the
North Pole and the equator is
900.
2.If a circle is drawn around the
Earth at each degree this is
equal to a line of latitude.
3. Equator = 0 latitude.
4. Lines of latitude run west
to east and are measured in
degrees north-south.
0
B-Longitude: Lines run northsouth and are measured in
degrees west-east.
0
1-0
longitude = the Prime
Meridian.
Greenwich England.