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How do physical processes shape Earth’s surface?
THE PHYSICAL WORLD
PLANET EARTH
OUR SOLAR SYSTEM• Sun at the center
• 8 known planets
• Mercury, Venus, Earth, Mars (inner planets)
• Jupiter, Saturn, Uranus, and Neptune (outer planets)
• Jupiter is largest
• Pluto is a dwarf planet---too small; not enough gravitational pull
SOLAR SYSTEM CONTINUED• Inner planets are terrestrial
planets---have solid, rocky crusts
• Only Earth has temps to support life
• Outer planets are gas giant planets---gaseous and less dense
• Asteroid belt btwn Mars and Jupiter
EARTH• Circumference of 24,900 miles
• 70% of surface is water---all water on Earth makes up the HYDROSPHERE
• 30% is land---LITHOSPHERE
• Air we breathe makes up the ATMOSPHERE(78% nitrogen, 21% oxygen, argon, others)
• All life makes up the BIOSPHERE
LANDFORMS• Natural features of Earth’s surface
• Largest are the continents
• CONTINENTAL SHELF: part of a continent that extends out underneath the ocean
• Lowest point on Earth’s crust: Mariana Trench (36,198 feet)
• Highest point: Mt. Everest (29,029 feet)
FORCES OF CHANGEHow is Earth’s structure related to the creation of continents,
oceans, and mountain ranges?
EARTH’S STRUCTURE• 3 main layers:
• 1. CORE: innermost layer; super-hot, solid inner core; super-hot liquid outer core (mostly nickel and iron)
• 2. MANTLE: middle layer; dense hot rock that is flexible
• 3. CRUST: outer layer; hard, rocky shell---broken into tectonic plates
CONTINENTAL DRIFT• Theory that the continents were
once joined and then slowly drifted apart
• Supercontinent was called Pangaea
PLATE TECTONICS• Def: activities of continental drift
and magma flow, which create many of Earth’s physical features
• MAGMA: molten rock (below surface)
• Belief is that this has been happening for 2.5-4 billion years
• Don’t know exactly what causes it
INTERNAL FORCES OF CHANGEHow does plate tectonics affect Earth’s surface?
COLLIDING PLATES• SUBDUCTION: process by which
oceanic plates dive beneath continental plates, often causing mountains to form on land
• ACCRETION: slow process in which an oceanic plate slides under a continental plate, creating debris that can cause a continent to grow
• Called convergent boundaries
SPREADING PLATES• SPREADING: process by which
magma wells up btwn oceanic plates and pushes them apart
• Called divergent boundaries
• Creates rifts
• Mid-Atlantic Ridge
FOLDS AND FAULTS• FOLD: a bend in layers of rock,
sometimes caused by plate movement
• FAULT: a crack or break in Earth’s crust
• FAULTING: process of cracking that occurs when the folded land cannot be bent any further
EARTHQUAKES• Sudden, violent movements of the
lithosphere along fault lines
• Caused by built up tension btwn plates
• Measured by the Richter Scale
VOLCANOES• Mountains formed by lava or
magma that breaks through the Earth’s crust
EXTERNAL FORCES OF CHANGE
WEATHERING • Def: chemical or physical
processes that break down rocks into smaller pieces
• Physical weathering involves physically breaking down rocks into smaller pieces
• Chemical weathering changes the chemical makeup of rocks
EROSION• Def: the movement of weathered
rock and material by wind, glaciers, and moving water
• GLACIER: large body of ice that moves across the surface of the Earth
• MORAINE: piles of rocky debris left by melting glaciers
SOIL BUILDUP• Five factors of soil formation
• 1. Climate: wind, temp, and rainfall determine type of soil
• 2. Topography: affects flow or runoff water
• 3. Geology: determines parent material
• 4. Biology: adds organic matter to soil
• 5. Time
EARTH’S WATERWhat drives the water cycle?
THE WATER CYCLE• Def: regular movement of Earth’s
water from ocean to air to ground and back to the ocean
• Total amount of water on Earth does not change
• Sun drives the cycle by evaporation…
EVAPORATION• Def: the changing of liquid water
into vapor
• Water vapor is gathered in the air
• Warm air holds vapor better than cool air
• Air cools, water condenses…
CONDENSATION• Def: process of excess water vapor
changing into liquid water when warm air cools
• Tiny droplets form together to create clouds
• When they get too full, they release the water
PRECIPITATION• Def: moisture that falls to Earth as
rain, sleet, hail, or snow
• Precipitation sinks into the ground
• Collects in streams and lakes
• Gets returned to oceans
• Hakuna matata!
BODIES OF SALT WATER• 70% of Earth is water
• 97% of that is one continuous body of water
• Divided into 5 oceans:
• 1. Pacific
• 2. Atlantic
• 3. Indian
• 4. Arctic
• 5. Southern
DESALINATION• Def: the removal of salt from
seawater to make it usable for drinking and farming
• Expensive process
BODIES OF FRESH WATER• 3% Earth’s water is freshwater
• 2/3 is trapped in glaciers and ice caps
• GROUNDWATER: water located underground; supplies wells and springs
• AQUIFER: underground water-bearing layers of porous rock, sand, and gravel