1. Chapter 3 – Models of the Earth

2. Section 3.1 Finding Locations on Earth
Objectives
Distinguish between latitude and longitude.
Explain how latitude and longitude can be used to locate places on Earth’s surface.
Explain how a magnetic compass can be used to find direction on Earth’s surface.

3. EARTH REFERENCE POINTS
AXIS OF ROTATION
NORTH POLE
SOUTH POLE
EQUATOR
NORTHERN HEMISPHERE
SOUTHERN HEMISPHERE

4. LATITUDE
The angular distance north or south of the equator. This set of circles are called parallels because they run east and west parallel to the equator

5. DEGREES OF LATITUDE
Measured and labeled as being north (N) or south (S) of the equator (0°)
Degree km (1/360th of Earth’s circumference).
Maximum values are at the geographic poles (90°N and 90°S).

6. Minutes and Seconds Degrees can be further subdivided:
Astrolabe – Early Instrument
Used To Determine Latitude

7. LATITUDE IN 1300’S

8. LONGITUDE
East-west locations established by using meridians, semi-circles that run from pole to pole.
Prime Meridian (0°) runs through Greenwich, England.
Longitude is the angular distance, measured in degrees, east or west of the prime meridian.

9. Degrees of Longitude
The meridian opposite the prime meridian is labeled 180°.
All locations east of the prime meridian have longitudes between 0° and 180°E, those west between 0° and 180°W.
Can also be subdivided into minutes and seconds.

10. Distance Between Meridians
The only place on the earth where 1° of longitude equals 111 km is at the equator. Why?
All meridians (lines of longitude) meet at the poles, so the distance measured by a degree of longitude decreases as you move from the equator toward the poles.

11. LATITUDE & LONGITUDE (We Make A Grid To Tell Location)

12. WHERE ARE WE? (Latitude Comes First, Then Longitude)
Fall City - 47o33'59"N, 121o54'08"W
North Bend - 47o29'45"N, 121o47'19"W
Snoqualmie - 47o31'27"N, 121o49'03"W

13. a globe it is a straight line.
Great Circles
Any circle that divides the globe into halves.
Often used in navigation, especially by aircraft.
Shortest distance between any two points on a sphere.
On a map a GC is curved, on
a globe it is a straight line.

14. Finding Direction
One way is to use a magnetic compass. This is because of the earth’s magnetosphere.

15. Geomagnetic Poles
The earth acts like it had a giant bar magnet inside it. It is tilted relative to the geographic poles.
A compass needle points to the geomagnetic pole.

16. Magnetic Declination
The angle between a compass reading and true north, measured in degrees east or west of the direction of the geographic North Pole. A compass reading is only accurate along the line of 0° magnetic declination.

17. Polar Wander
The geomagnetic pole, over time, changes position. Today it is slightly west of Ellesmere Island (Canada).

18. The Global Positioning System (GPS)
A global network of 24 satellites. Radio signals from 3 satellites allow a GPS receiver to calculate the latitude, longitude, and altitude of the receiver. Accurate to ±15 meters.

19. ASSIGNMENT Outlining Review Section Outline 3:1 3.1 Key Terms
3:1 Directed Reading Worksheet