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The Changing Earth
Chapter 2 Section 1 & 2
The Structure of the
Earth
Geology: the study of the
earth’s physical structure
and history—is a relatively
new science. It deals,
however, with very ancient
history of the earth.
The Earth’s Inner
Structure
The earth is made of mostly of iron, nicked
and rock. They are arranged in four layers;
Crust: is a band of solid rock at the surface of
the planet. It 25 to 30 miles thick beneath the
continents & 5 to 10 miles in the oceans.
Mantle: A soft layer of molten rock. It extends
for 1,800 miles toward the center of the Earth.
Magma: is molten rock, is created when the
mantle melts.
Cont.
Core: is the solid metallic center of
the earth and is made up of iron and
nickel, which are under tremendous
pressure.
Outer core: 1,380 miles thick
Inner core: 760 miles radius
The Earth’s Interior
Earth is the only planet in our solar system
capable of supporting many forms of life.
Atmosphere: gases
surrounding the
earth; oxygen we
breath, protects the
earth from radiation,
& provides weather.
Lithosphere: some
is located in the
ocean & others are
found huge
landmasses called
continents.
Hydrosphere: is
made up of the
water elements on
the earth (oceans,
seas, rivers, lakes, &
rain)
Biosphere: the part
of the earth where
plants & animals
live.
Continental Drift Theory
In 1915, the German geologist
and meteorologist Alfred
Wegener first proposed the
theory of continental drift,
which states that parts of the
Earth's crust slowly drift atop
a liquid core. There was once
a “supercontinent” on earth &
he called it Pangaea. 180
million year ago, Pangaea
began to break into separate
continents. The fossil record
supports and gives credence
to the theories of continental
drift and plate tectonics.
Section 2: Bodies of
Water
Ocean & seas: the ocean cover about
71 % of our planet.
Even through there is only one ocean; it
is divide in 4 main parts
Atlantic Ocean
Pacific Ocean
Indian Ocean
Artic Ocean
Ocean Motion
The salty water of the ocean circulates
through three basic motions:
Currents
Waves
Tides
The motion of the ocean helps distribute
heat on the planet. Winds blows over the
ocean & are either heated or cooled by the
water. They then blow over land causes
warmth or coolness.
Hydrologic cycle
Is the continous circulation of water between
the atmosphere, the ocean, & the earth.
Landforms on Earth’s
Surface
Tectonic forces inside the Earth have
produced four major types of landforms
Mountains & hills: Mts. tend to be more
sparsely populated than hills and usually
lie at 2,000 to 3,000 ft. above sea level. Ex:
the Rocky Mts., Andes Mts., the Alps, Ural
Mts. & the Himalayas. Hills are lower,
rounded, and generally less steep than
Mts.
Cont.
Plains are relatively low-lying, level areas
that in many cases are gently rolling.
Largest plains in the world are the Central
Plains of N. America, the Amazon Basin in
S. America, North European Plains & flat
plains of central Australia.
Plateaus are relatively level like plains, but
they located at higher elevations. They
have at least one steep side where a line
of cliffs, escarpment, separates the
plateau from neighboring low-lying areas.
Landforms
Oceanic Lanforms
The seafloor has landform similar to those
above water.
It has ridges, valleys, canyons, plains &
mountains chains similar to those on the
continents.
Islands are form by volcanic action, deposit of
sand, or deposits of coral skeletons.
Longest Mountains range is Mid-Atlantic
Ridge.
Sonar