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Published byJerome Gervase Walker Modified over 9 years ago
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The Globe How to describe where you are, and how to find new places.
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Intelligence Competition To find who is smarter, males or females, we are going to conduct a scientific experiment. I will give the name of a place in Arizona. When you have located that place on the map, raise your hand. This is a timed test. The first 5 times will count for the team score. Lowest times win. Ladies first. No cheating!
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Ladies find - Sasabe Arizona
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Guys find - Holy Joe Peak
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HINT!!! Look in I 9
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You need - Coordinates (= two numbers) One set across One set down Start at logical point - on flat map, upper left corner (just like reading.) Use letters or numbers I 9 BINGO!
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Can we do this for the Earth? (Photo of Earth here)
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We have a problem! Spheres don’t have a logical starting point.
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BUT, The Earth rotates on its axis. North Pole South Pole This gives us Two logical Starting points. (How would You know if You were There?) Axis
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You could then draw lines from one pole to the other.
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Now, if you divide each of those lines in half and draw a line through the midpoints… You get the Equator
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Next, draw lines around the Earth parallel to the equator.
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Finally, we have our grid!
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Remember from math - Circles are divided into 360 degrees.
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Latitude Measures degrees north/south –also called parallels Starting point: Equator 0º Ending point: Poles 90°N,S Equator separates North/South Hemispheres Equator is a great circle –the only parallel great circle –What in the world is a GREAT CIRCLE?
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A great circle is the edge of a cut through the Earth that passes through Earth’s center
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Longitude Measures degrees east/west –also called meridians Starting point: Prime Meridian 0º Ending point: International Date Line 180º Separates East/West hemispheres –every meridian and the one opposite make a great circle
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Each Degree of Latitude (or Longitude at the Equator) Represents ~69 miles (360 x 69 = 24,840mi) To be more precise: –each degree 60 minutes ~1.15 miles –each minute 60 seconds ~101 feet
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Distance for a degree of longitude varies
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Written Form latitude, longitude degrees minutes (&seconds) Phoenix: 33º 26’ N, 112º 04’ W MCC: 33º 25’ N, 111º 49’ W
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International Meridian Conference 1884 27 nations Established Royal Observatory at Greenwich England as the Prime Meridian
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Map Projections A globe is not always the best representation of the Earth –Doesn’t show local detail –Lacks convenience - not portable
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Map Projections But a globe is the only true representation of: –direction –area –shape –distance
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