2 Section I. Planet EarthWhat do you know about the Solar System?
3 A. Our Solar System The sun is at the center of our Solar System Sun creates a strong pull of gravityKeeps objects such as Earth revolving around the Sun
4 Our Solar SystemRevolution – in astronomy, the Earth’s yearly trip around the sun365 ¼ daysWhy is the ( ¼ ) important to know??Rotation – the Earths daily trip turning on its axisHow long is a day?
5 In history….People believed that the solar system revolved around EarthGeocentrismConnected to religionBut it was Galileo (16th century) that actually fought for the now accepted theory that we were the ones movingHeliocentrism
6 What’s the idea behind the theories? Why would people think we were geocentric??Which theory would you side with if you had to choose?What would happen without the sun?
8 The “Classical” Planets: Neighbors in Space Before it was believed we had nine planets now we just classify eightInner Planets (Terrestrial)MercuryVenusEarth (only one with sustainable life)Mars
9 The “Classical” Planets: Neighbors in Space Outer Planets (Gas Giants)JupiterSaturnUranusNeptuneAll have moons except Mars & VenusThere are also asteroids, comets and meteoroids
10 Pluto……..planet?? Discovery Channel, August 24th, 2006 [Much-maligned Pluto doesn't make the grade under the new rules for a planet: "a celestial body that is in orbit around the sun, has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a ... nearly round shape, and has cleared the neighborhood around its orbit.“][Pluto is automatically disqualified because its oblong orbit overlaps with Neptune's.]
11 B. Getting to know the Earth The earth is divided into categoriesHydrosphere – part of Earth made up of oceans, lakes, rivers, and other bodies of waterLithosphere – part of Earth made up of continents and islandsAtmosphere – a layer of gases that surrounds the EarthBiosphere – the part of the Earth that supports life
14 Atmosphere = Air Above earth’s surface you have a layer of gases 78% nitrogen, 21% oxygen and the rest argon and other gasesOur natural vegetation is essential to the recyclement of our oxygen
15 Biosphere = life The part of earth that supports life Life outside of the biosphere only exist with mechanical life support systemSpace shuttle
16 Air + Land + Water = Biosphere! Bio=life! Hence, Biology….
17 C. LandformsNatural features of the earth’s surface that vary in shape and elevation4 major landforms-MountainsHillsPlateausPlainsAlso have valleys, canyons, and basinsAll contain rivers, lakes and streams
18 Underground Landforms Landforms underwater are as diverse as those found on dry landRange from flat plains to mountain ranges, cliffs, valleys and deep trenches
19 Earth’s most visible landforms From space the most visible landforms are the 7 continentsAustraliaAntarcticaEuropeAsiaNorth AmericaSouth AmericaAfrica**** Locate continents on your map ****
20 Continental ShelfPart of a continent that extends underwater
32 Plate Tectonics Plates are continually moving At times they may crash, pull apart, grind or slide past each otherConstantly changing the face of the planetThey push up mountains, create volcanoes, and produce earthquakesTheory: heat rising from the core create slow-moving currents within the mantle which then shift the plates around
36 2. SubductionA heavier sea plate dives beneath the lighter continental platePlunging into the earth’s interior, the sea plate becomes molten materialThen as magma it bursts through the crust to form volcanic mountainsAndes
37 3. AccretionPieces of earth’s crust come together slowly as the sea plate slides under the continental plateCreates underwater mountains with steep sides and sharp peaksCreates new land often island chain at the boundary
38 4. Spreading Sea plates pull apart Deep cracks (rift) allow magma from within the earth to well up between the platesMagma hardens to build undersea volcanic mountains or ridgesSpreading keeps Europe and N. Ame apart
39 5. Folds (bends)Moving plates squeeze the earth’s surface until it buckles or creates folds in layers of rock
40 6. FaultsPlates grind or slide past each other creating cracks in earth’s crustWhen land can no longer be folded the earth’s crust cracks and breaks into huge blocksSmall tremors occurSan Andres Fault in CA
41 7. Earthquakes Sudden, violent movements of plates along a fault line Dramatically change the surface of the land and the floor of the oceanHappen when different plates meet each other. Tension builds up as the plates stick. The strain becomes so intense that the rocks suddenly snap and shift. This releases stored up energy along the fault. Eventually the ground trembles as sends shock waves which are felt
42 Ring of Fire Earthquake and volcano zone surrounding the Pacific Ocean Boundary where the plates that cradle the Pacific meet the plates that hold the continents surrounding the ocean
43 8. VolcanoesVolcanoes are mountains formed by lava or magma that breaks through the earth’s crustOften rise along plate boundaries where one plate plunges beneath anotherIn such a process the rocky plate melts as it dives downward into the hot mantle. Pressure builds, a funnel is created and hot magma rushes to the surface. The lava will eventually create a volcano
44 VolcanoesAs a moving plate passes over these hot spots, molten rock flowing out of the earth’s surface may create volcanic island chainsHawaiian IslandsMolten rock may also heat underground water causing hot springs or geysersYellowstone
45 External Forces of Change Wind and water change the earth’s surface (two processes)Weathering – process that breaks down rocks on the earth’s surface into smaller piecesErosion – wearing away of the earth’s surface by wind, glaciers, and moving waterWeatheringWind ErosionGlacial ErosionWater Erosion
46 Weathering Either physical weathering or chemical weathering Physical – when large masses of rock are physically broken down into smaller piecesWater seeps into the cracks in a rock and freezes, then expands and causes the rock to splitChemical – changes in the chemical makeup of rocks (transforming their minerals or combining them)Water mixed with carbon dioxide from the air easily dissolves certain rocks such as limestone
47 Wind ErosionMovement of dust, sand, and soil from one place to anotherCan be devastating or beneficialDust BowlChina Yellow River basin is thickly covered with loess (fertile yellow-gray soil deposited by wind)
48 Glacial ErosionGlaciers – large bodies of ice that slowly move across the earth’s surfaceGlacial movements change the landscape by destroying forests, carving our valleys, etcHowever, when glaciers melt and recede they leave behind large pules of rocks and debris (moraines)Moraines can form long ridges of land or create glacial lakes
49 Water Erosion Most significant cause of erosion Fast moving water – rain, rivers, streams, and oceans – cuts into the land wearing away the soil and rockThe resulting sediment (small particles of soil, sand and gravel) act like sandpaper and cut away at landGrand Canyon
50 Section 3 – Earth’s water Hydrosphere!!Almost all of the hydrosphere is salt water found in the oceans, seas and seawater lakesThe remainder is freshwater found in lakes, rivers, and springs
51 Water Cycle Regular movement of water through Evaporation – sun, changing liquid into vapor or gasCondensation – excess water vapor changes into liquid formForms cloudsPrecipitation – rain, snow, or sleet that sinks into the grounds and soon is evaporated again
52 Bodies of Salt Water (97%) OceansPacificAtlanticArticSouthernIndianSeas, Gulfs, and BaysDesalination – conversion saltwater into freshwater
53 Freshwater (3%) Lakes, Streams, and Rivers Groundwater – freshwater that lies beneath the earth’s surfaceComes from rain and melted snow that filter through the soil and from water that seeps into the ground from lakes and riversCan use wells to tap into freshwaterAquifer – underground porous rock layer saturated with water in the form of streams
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