Download Maps & Projections - New York Science Teacher

DO Now
1.
2.
3.
List differences between latitude
and longitude
Why are there time zones on Earth?
If it 2pm in New York State and
California is 45 degrees west, what
time is it in California?
Mapping the Earth
Measure the Earth



Relationship between altitude of
Polaris and a persons latitude in the
Northern Hemisphere
The true shape of Earth
Observations of the sky are affected
by Earth rotations
Shape of the Earth

Perfect sphere• Polar diameter
equals equatorial
diameter (PD=ED)

Earth has a slight
bulge
Oblate Spheroid
flattened slightly at the poles
and bulging at the equator
 Polar Diameter=12,715 km
 Equatorial
Diameter=12,756km
 Therefore ED > PD

Proof that Earth is an Oblate
Spheroid
1.
2.
Photographs from space (most
direct)
Altitude of Polaris (north star)
•
•
Polaris is almost located directly over
the North Pole
As an observer travels north or
south the altitude of Polaris changes
POLARIS (AKA North star)
More Proof
3. Gravitational Measurements
•
Differences in weight of an
object at the equator and the
poles
4. Early Observations
•
As a ship sails away from shore
it appears to disappear from the
bottom up
Determine Polaris
1.
Latitude is equal
to the angle of
Polaris in the
Northern
Hemisphere
What is the latitude of the
observer?
1.
2.
3.
4.
10° North
20° North
40° North
70° North
Polaris

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Is always north of the north pole
It is a celestial object
It circumvents the Earth
Maps & Projections
Latitude and Longitude