Chapter 1 Introduction to the Earth

Transcription

1 Chapter 1 Introduction to the Earth

2 What is Geography? The study of the earth as the home of humankind. Greek - Eratosthenes Father of Geography Geo means Earth Graphy means to write Study how things are different from place to place The study of where things are on the earth and the reason for the location Asks two simple questions - Where and Why? Where are physical featured found? Why are they there?

3 Why are some places deserts and some places are forests? Why are there mountains in some places and not in other places?

4 Cultural Geography - is the study of where and why human activities are located where they are. Religion, migration, businesses, cities Physical Geography - Where and why natural forces occur. Climate, Landforms, vegetation

5 Science and Geography The Scientific Method Theory Highest order of the understanding for a body of information Testable and repeatable with same results Well supported with many independent strands of evidence New observations and evidence can change theories Geocentric vs. Heliocentric

6 Earth s Four Spheres Four systems all interacting at various levels Three non-living spheres and a fourth living sphere Atmosphere A thin layer surrounding the Earth Formed by gasses from the interior of the earth and all life over time Hydrosphere All water in the atmosphere, on the surface and near the surface Liquid, gas and solid

7 Lithosphere The Earth s crust and a portion of the upper mantle Includes 7 continents and all landforms Biosphere All organisms, plants, and animals overlaps the other three spheres Seafloor to 5 miles into the atmosphere 7

8 The size and shape of the Earth Pythagoras determined the earth is a sphere ( BC) Eratosthenes (247 BC) 26,700 miles circumference Actual circumference 24,900 miles Sir Isaac Newton Bulged at equator, flattened at poles Oblate spheroid Topographic irregularities Mountains, valleys, Mt. Everest feet Marianas Trench feet

9 The Geographic Grid System for accurate locations Pinpoint with mathematical precision Two sets of lines that intersect at right angles Latitude measure North-South of Equator Longitude measure East-West of Prime Meridian

10 Eratosthenes Angle of shadow on earth Equator Latitude Divides the Earth into a Northern and Southern hemispheres Angle north or south of the Equator Latitude increases as one travels north or south of the Equator 0 degrees at Equator 90 degrees at Poles

11 Parallels of Latitude Parallels are always parallel to one another Parallels are equally spaced between the equator and the poles 1 degree of latitude = 69 miles Parallels of Latitude are true east/west lines Political Boundaries 11

12 Significant parallels of latitude Equator 0 o Tropic of Cancer 23.5 o N Tropic of Capricorn 23.5 o S Arctic Circle 66.5 o N Antarctic Circle 66.5 o S North Pole 90 o N South Pole 90 o S

13 Bands of Latitude Low latitude - Equator to 30 o N/S Midlatitudes - 30 o to 60 o N/S High latitude - greater than 60 o N/S Equatorial - within a few degrees of the equator Tropical - within the tropics (23.5 o N to 23.5 o S) 13

14 Longitude Description of east-west location Much harder to determine and measure No natural division Earth spins on it s axis Age of Discovery 1707 British naval disaster Star charts John Harrison - Clockmaker 13 Prime meridians 1884 conference

15 A meridian is a line connecting all points along the same longitude Measured East and west of the Prime Meridian (Greenwich) Meridians are spaced farthest apart at the equator and converge to a single point at the poles Divides the Earth into Eastern and Western Hemispheres 180 degrees East and West International Date Line

16 Measuring Latitude and Longitude Measurement based on a circle 360 degrees in a circle 60 minutes in one degree 60 seconds in a minute Gives each location on Earth a unique identifier Can provide very accurate measurement Degrees, Minutes and Seconds 35 o N 118 o W

17 Earth s Place in the Universe The Universe contains at least 125 billion galaxies Our galaxy, The Milky Way contains 300 billion stars The center of our galaxy contains a super massive black hole 50 billion planets in The Milky Way, 500 million in habitable zone 17

18 The Solar System, Sun and Earth 1 Sun 8 Planets 176 moons Thousands of comets 4.6 billion years Contains all life that we know

19 Earth-Sun Relations Plane of the Ecliptic Earths orbit is not perfectly circular Closest 91.5 million miles Furthest 94.5 million miles The earth revolves around the sun. 365 days 5 hours, 42 minutes, 46 seconds Leap years

20 The Reason for the Seasons Five factors are responsible for the seasons Earth s revolution around the sun (365 days) The rotation of the earth (24 hours) The tilt of the Earth (23.5 degrees) Tilt of the Earth remains fixed Appears as a spheroid to the sun 20

21 The Annual March of Seasons Caused by the angle at which the suns rays strike the surface of the earth June Solstice - June 21 Sun perpendicular to Tropic of Cancer 24 hours of sun at Arctic Circle 24 hours of darkness at Antarctic Circle

22 September/March Equinox Sun perpendicular to Equator All locations on Earth has 12 hours of light December Solstice - December 21 Sun perpendicular to Tropic of Capricorn 24 hours of sun at Antarctic Circle 24 hours of darkness at Arctic Circle

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