Download MAPPING THE EARTH

MAPPING THE EARTH
What do these have in common?
Model
• Representation of something else
• Examples?
• Globe, equation, graph, chart, map
• Why?
Earth, universe are too big. Time is too long.
True Shape of the Earth
• Slightly Oblate sphere
Flattened at poles Bulges at equator
• Circumference at Poles:
•
40,008 km
• Circumference at Equator:
•
40,076 km
WHY?
• Earth rotates and the centrifugal force when it
spins causes it to bulge at the equator.
• Think of a little girl in a dress that twirls around.
The dress flares out.
• Or think of the force that pulls you out when on a
merry-go-round!
EVIDENCE THAT THE
EARTH IS ROUND
1. Observations of ships on the
Horizon
2. Lunar Eclipse - Shadow of the earth on
the moon is curved
3. Altitude of Polaris
• More on that later!!!!
4. Best Evidence that Earth is
Round
Pictures from outer space
EARTH’S SPHERES
•
Atmosphere - Envelope of
gases surrounding the earth
• Made of gases so least dense sphere,
1.3 x 10-3 g/cm3
ESRT Page 14
• lithosphere - Earth’s solid outer layer,
“shell of the earth”, crust and upper solid
part of the mantle
Approximately
100 km thick
Most dense sphere,
2.8 – 3.0 g/cm3
ESRT Page 10
• Hydrosphere - Layer of liquid
water that covers the earth
• 70% of earth’s surface
• ESRT Page 1
Biosphere
• The portion of the
earth and its
atmosphere that can
support life.
Atmosphere
Hydrosphere
Lithosphere