Geography Exam 1 Review 09 25 2013 What is Geography geo means earth ography means to describe Approaches Systematic worldwide looks at one subject soil is systematic Regional grouped by arbitrary homogenous characteristics core within sphere of influence core has same basis Man environment relationship of one to the other their influence on one another Earth Oblate spheroid Diameter is 7927 miles 27 miles shorter through the poles Most of earths water is in the southern hemisphere and land masses in the northern 72 water hemisphere Crust is 2 7 SG 20 miles thick Mantle is 3 3 SG specific gravity Water is 1 SG Specific Gravity ratio density of a substance to density of reference Map and Grid Systems Map properties show direction azimuth military terminology show distance show area and how areas are relative to each other area and shape cannot be shown on the same map show shape area and shape cannot be shown on the same map 2 dimensional surfaces are an issue Projections Points of contact are clear away from p o c increases distortion Planar plane map center is most accurate standard point Conic map where cone touches most accurate point standard line Cylindrical map where cylinder touches its most accurate point best for navigation most used map Mercator projection Greenland looks larger due to stretch but is actually 1 0 size of south America Diagrams of Maps Scale Distance on the map that represents distance on real surface Verbal 1 inch 1 mile Graphic 0 1 2 3 4 Fractional 1 62500 used to be US standard standard map used in USA is 1 inch 2000 ft 1 250 000 means 1 inch 4 miles Small scale shows more vs large scale show less as dominator gets larger actual number gets smaller Example Diagram 4 inches 1 in 1 mile 4x8 32 miles 1 in 2 miles 8x16 128 miles 8 inches 1 in 4 miles 16x32 512 miles Surveying Metes Bound Survey property defined by things in landscape problem if item removed property boundaries difficult to find most original colonies laid out this way Grid System Latitude imaginary line running through east west measures angular distance north south Longitude running through north south angular distance east west 0 180 degrees prime 0 90 degrees equator to poles meridian to international date line Prime Meridian is in Greenwich England line of longitude Lines of latitude are parallel to each other The equator bisects the Earth Lines of Longitude are wide at the equator and grow less wide north south until they meet at the poles Example Diagram Contour Lines Line on the map that connects points of equal elevation Contour Interval vertical distance between two contour lines Bench Marks BM wooden posts with brass plates that tell elevation of area With steeper slopes the contour lines are much closer tightly together With gentle slopes the contour lines are much farther apart Interpolate estimate elevation between contour lines Slope Consists of 1 Shape and 2 Gradient Gradient ratio Percent primarily used by construction Degrees primarily used by geologists Vertical Distance Slope Horizontal Distance Example Diagrams What Causes Seasons Earths tilt on its axis 23 5 degrees earth turns 15 degrees every one hour Earths rotation on its axis 1 day lasts 48 hours on earths surface Revolution around the sun Parallelism of axis Time Baton Rouge 1pm Baton Rouge 11 30 pm sunday New York 2pm New York 12 30 am Monday morning L A 11am L A 9 30 pm 24 time zones on earth Terms Surface Water ground running underwater called overland flow or runoff forms gullies or rills which eventually form streams and rivers Overland Flow function of rainfall intensity and the ground absorbing it called infiltration anything not soaked in is overland flow or run off Rainfall Important Aspects intensity inches per hour length of storm all leads to how much overland flow we get Geomorphology Geomorphology studies landforms and the shape of things on surface Uniformitarianism present is key to the past Limitations change in intensity and process Systems Open and Closed Equilibrium there s no change constant If the energy input equals the energy output Threshold something causes a change to the system Steady State moving towards equilibrium and not really changing Pleistocene Time period of the last 2 5 million years Glacier formation and melting Most f earths topography is no older then Pleistocene Geologic and climatic changes of Pleistocene were critical in shaping most landscapes Endogenic Processes result from interior of the Earth faulting volcanoes etc create topography on surface Exogenic Processes occur from outside the Earth rainfall temperature causes weathering breaking rock down erosion rocks on surface are continually recycled deposition of water and ice Speed of Infiltration 1 Grain Size size of things that make up the ground from very small clay to silt to sand to gravel to boulders 2 Porosity how many holes does something have 3 Permeability how well molecules are connected and if they allow water to flow through 4 Slope steep slope means water can run off very fast not steep slope means water will sink in and not run off 5 Vegetation vegetation absorbs water and holds it in no vegetation means water runs off very quickly Hydrologic Cycle transfer of water from water bodies to atmosphere to ground evaporation precipitation condensation etc see figures in textbook Earths Crust Always changing being formed deformed moved and broken down by physical chemical and biological processes Earths crust is about 20 miles thick and about 3 miles down it floats above the mantle 18 600 ft above the mantle crust Continental Drift Alfred Wegner 1950 1960 idea that landmasses migrate which he called continental drift Pangaea is the name he gave one land mass meaning All Earth Tectonic greek word teckonikus meaning building or construction Earths crust changes as a result of internal forces Plate Tectonics include the processes of upwelling magma lithosphere plate movements sea floor spreading and lithosphere subduction earthquakes volcanic activity folding and faulting Plate Tectonics move at speeds of 6cm per year 2 4 inches convection currents in the asthenosphere and upper mantle are dragging them around Sea Floor Spreading Sea floor not permanent it is constantly moving moves laterally Earths crust along the continental margins warps up or down in adjustment to strain and erosion Sea level changes in 3 ways 1 Tectonic 2 Eustatic 3 Isotatic Tectonic changes in plates can raise or lower areas Eustatic