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Unformatted text preview: Geography 120 Exam One Olivia Guidera Earth’s Systems Science:- Earth = single entity- Interactions: physical biological chemical *systems are interlinked *humans are increasingly important agents in the earth system changing interactions: dams, mining - Earth’s Subsystems:- atmosphere- biosphere- hydrosphere- lithosphere - Radius of the earth = 6400 km / 4000 miles - radius from center to poles is shorter than the equator due to centrifugal force: pushes mass outwards *have more mass at the equator- Models of the Earth 1. Flat Surface 2. Sphere: the difference from the high and lowest points is so small compared to the ra- dius so we can model a sphere 3. Ellipsoid: takes into account radius vs poles 4. Irregular: topography, irregularities of the earth - Geographic Grid: orient ourselves in space - Latitude = North/South- Longitude = East/West - (Latitude, Longitude)- Motion Through Space- Rotation: earth moving on its axis - gives night and day- rotate approximately 1/ day ~ 365/ year - rate of rotation changing overtime - as masses redistribute of earth the rate changes - Ex. Japanese storm changed rate, glaciers changing distribution of water - Revolution (around the sun): - 1/ year - Perihelion: reaches area where passes earth closest to sun- Aphelion: reaches area where passes earth farthest from sun *difference of the two is 4.8 million km- average earth to sun distance ~150,000,000 km - Eccentricity: shape of orbit around the sun- NOT what gives us seasons- Tilt (GIVES us seasons): at ~23.5 degrees- tilts towards polaris (north star)- tilt varies on cycle at 41,000 m cycle- varies at 22.5 degrees - 24.5 degrees - causes seasonality to change, become more or less seasonal across earth- more tilt = more seasonality- less tilt = less seasonality (north star receives sun) Solstices: when the earth comes into most / least light June Solstice: - longest day for northern hemisphere- shortest day for southern hemisphere - When the earth reaches the position in its orbit where the North Pole is orientated most directly towards the sun December Solstice:- shortest day for northern hemisphere- longest day for southern hemisphere - When the earth reaches the position in its orbit where the North Pole is orientated most directly away from the sun *tilt towards or away Equinox: tilt not towards or away, half of the earth is illuminated - 12 hours of light and 12 hours of dark March Equinox: when the vertical rays of sun are striking the equator. - on this day all locations have twelve hours of sunlight and twelve ours of dark- ness September Equinox: when the vertical rays of sun are striking the equator. - on this day all locations have twelve hours of sunlight and twelve ours of dark- ness *both virtually the same Sun’s rays to earth are parallel - not all are 90 degrees, just at the declination: latitude at which the sun is dir- ectly overhead aka 90 degree angle from the ground - must be between 23.5 North and 25.5 South- everywhere else needs to have...
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This note was uploaded on 03/11/2012 for the course NUTRI 132 taught by Professor Anderson during the Fall '11 term at University of Wisconsin.
- Fall '11