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Home , Antarctic Circle, Arctic Circle, Equator, Tropic of Cancer, Tropic of Capricorn

in Different Dimensions Observing the World

Round? observation the key first step to ALL science driven by curiosity a process of discovery answer questions about how the world works knowledge improves quality of life

Or flat?

Calculate circumference ( C) using simple math: (, 235 B.C.) 360 o/7.2 o = C/500 ; C = 50 x 500 miles = 25,000 miles On June 21 (summer ), midday a shadow cast by a directly overhead, shining down a deep well in monument in Alexandria the city of Syene (Aswan) the Sun's rays of shadow made by sun shining on a ~5000 stadia = 500 mi ° ° monument at midday on June 21 in Alexandria 7 12' = 7.2 a well in Syene was 7o21’ Alexandria lies ~5000 stadia to the of Aswan (~ 500 miles ) Remarkable agreement with actual figure of 24,862 miles (40,010 km) – WOW.

1 Where in the World are we? How do we describe where we are on the ? (North-South) & (East-West)

based on angular relationships to Earth’s center grid system used to precisely describe locations on the Earth’s surface expressed in degrees (o) of arc  each is divided into 60 minutes (‘)  each minute is divided into 60 seconds (“)

90 °N () Latitude Longitude 180 °W 60 °N (180 °E) “parallels” = grid lines “meridians” = grid lines 30 °N that are parallel to the that intersect at poles 150 °W 0o = “Prime ” ° 0o at equator, 90 o at 0 (Equator) (Greenwich, England) 120 °W 90 °W 60 °W 30 °W poles Parallels (Latitude) 180 o = halfway around Meridians (Longitude) 0o-90 oN = N. Hemisphere 30 °S Earth 0° o o o o 0 -90 S = S. Hemisphere 60 °S 0 -180 to west of Everywhere on Earth’s surface: Greenwich = W. Hemisphere 90 °S 1o lat. = 60 nautical miles () 0o-180 o to east of 1’ lat. = 1 nautical Greenwich = E. Hemisphere

2 Equatorial View Polar View Special and Latitudinal Zones North Pole 90 °N North Pole 90 °E (90 °N) 120 °E 60 °E 60 °N Circle northern high latitudes (66.5 ° N) 60 °N 30 °N 150 °E 30 °E mid-latitudes

Prime ° ° ° ° ° ° Meridian 30 N 150 W 120 W 90 W 60 W 30 W Tropic of (23.5 ° N) 180 °W North Pole ° ° 0 ° 0 Equator (180 E) 90 °N 180 °W 0° Prime (180 °E) Meridian 0° (Equator)

30 °S 150 °W 60 °N 30 °W

Tropic of Capricorn (23.5 ° S) subtropics ° 30 °N 30 °S 60 S 120 °W 60 °W Equator ° 0 90 °W mid-latitudes 90 °S Circle ° South Pole (66.5 ° S) 60 S Smith College southern high latitudes (90 °S) Lat. 42°19 ’ N, Lon. 72°38 ’ W South Pole

The Earth’s tilt – the reason for the

Earth's axis of (23.5 ° tilt)

Arctic Circle North Pole

Tro pic of Ca nce S e r Plane of Earth's orbit around Sun (aka, “the ”) qua tor Tro pic of U Ca pric orn N

South Pole

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