How do physical processes shape Earth’s surface? THE PHYSICAL WORLD How do physical processes shape Earth’s surface?

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 CHANGE How 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 CHANGE How 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

What drives the water cycle? Earth’s water What 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