# Lab # 21 Latitude and Longitude

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```Latitude and Longitude
Lab # 1
Experiment # 22 in text
Page 291
After the lab is complete
you will be able to:
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Explain the grid system used for locating
places and features on Earth.
Use Earth’s grid system to accurately locating
places and features on Earth.
Explain the relationship between latitude and
the angle of the North Star (Polaris) above the
horizon
Earth’s Grid System
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A system of North-South and East-West lines
on a map that form the basis of locating points
on Earth.
Latitude – North-South distance on Earth
• They are a measured distance North or South
from the equator.
• They are horizontal lines that circle a globe.
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Longitude – East-West distance on Earth
• These lines mark a distance East or West from the
prime meridian.
• They are the vertical lines that circle the globe.
Important Latitude Lines
http://www.worldatlas.com/aatlas/imagee.htm
Latitude Lines
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They run East to West and they measure the
distance North or South of the Equator
Equator is the only great circle that is also a
latitude line
• Great circles - cut the globe in half
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The tropic of Cancer and Capricorn are small
circles
• Small circles - do not cut the globe in half
How to Determine Latitude
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Latitude line may be drawn at any interval
from the equator
On page 292 draw a line through B (this is the
equator)
From the equator draw a line to point C
The line connecting these two points will have
a 45O angle. This point is therefore 45O N
latitude
Figure 22.3 pg 292
45O Angle
C
Equator
B
Thus point C is 45O N latitude
Longitude Lines
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Run North to South; they measure a distance east or
west of the Prime Meridian.
Where to put the prime meridian?
Greenwich, England here because at the time England
was the head of the scientific community.
Before there were many meridians that longitude was
based off of.
The Prime Meridian was used to standardize all of the
other Meridians.
All longitude lines are great circles.
Prime Meridian
North Pole
London, England
South Pole
Using Earth’s Grid System
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Using both parallels of latitude and meridians
of longitude it is possible to accurately locate
any point on the surface of the Earth.
Where 90O (N or S) is the maximum distance
from the Equator and 180O is the maximum
distance from the Prime Meridian.
To be more precise we can break down
degrees into minutes and seconds.
• Fractions of a degree (not covered in this class)
Labeling Latitude and Longitude
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For Latitude Lines:
• North (N) or South (S) must be labeled for all
latitudes except the Equator (0O)
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For Latitude Lines:
• East (E) or West (W) must be labeled for all
longitudes except the Prime Meridian (0O) and the
International Date Line (180O)
Lab Report
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Due Next Class:
• Questions on page 321 #1-7, 11 &amp; 12
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