1. Models and Dimensions of Earth
I. Model=
Simplified representation of an object or idea
A. Types and Examples of Models:
1. __________________ - provides us with information through our sense of sight.
PHYSICAL
Geographical Globe

2. Models and Dimensions of Earth
Mechanical
2. __________________ - a physical model with moving parts so that it can perform the functions or movements as the original model.
Model Electric trains

3. Models and Dimensions of Earth
Mathematical model
3. __________________ - mathematical relationships expressed by symbols, formulas, and equations.
Equations

4. Models and Dimensions of Earth
Graphic model
4. __________________ - a graph to provide a “picture” of a relationship of symbols, formulas, and equations.
Temperature vs. Month Graph

5. Models and Dimensions of Earth
Mental
5. __________________ - models that can only exist in someone’s mind.
Water is made of 2 Hydrogen and 1 Oxygen molecules

6. II. Shape of Earth Oblate spheroid Flattened sphere
________________ - _________________
______________________
Diagram of an __________________________
Flattened at the poles
Bulging at the equator
Oblate spheroid
NOT TO SCALE
Polar diameter
Equatorial Diameter

7. greater
4. Earth’s equatorial circumference is ______________
than its polar circumference.
a. Equatorial circumference - ___________________
b. Polar circumference - ______________________
24,900 miles
24,860 miles

8. . B. Causes of Earth’s Shape
1. _____________________ an inward pulling force. This force pulls equally in all directions and causes earth to be _______________________.
Gravity
an oblate sphere .
Key___________ = force of gravity

9. X Y Centrifugal Force Rotate faster 24 hours 24 hours
2. ________________- an apparent outward force caused by the spinning (or rotating) of earth on its axis. This force causes earth to _________________.
a. The faster the rotational speed, the ____________ the centrifugal force.
b. (1) How long does it take each location to make one complete rotation?
X___________
Y___________
Rotate
faster
24 hours
24 hours X Y

10. (2) Which location, X or Y, travels a greater distance to make one complete rotation? ____________
(3) At which location, X or Y, is the rotational speed greater? _____________
(4) At which location, X or Y, is centrifugal force greater? _____________
c. Therefore, the greater centrifugal force causes earth to bulge at the __________________________.
Location X
Location X
Location X
Equator X Y

11. C. Evidence of Earth’s Shape
Photographs from space reveal that Earth is
_______________________
2. Observations of ships on the horizon
Round
The gradual “appearance” or “disappearance” of a ship over the horizon is evidence that earth’s surface is ____________________.
Curved

12. 3. Observations of an Eclipse of the Moon (as viewed from Earth)
a. As viewed from space:
As the moon orbits Earth, and travels from position 1 to position 2, it passes through ______________________________________.
Earth’s shadow

13. b. As viewed from Earth:
c. Earth’s shadow on the moon (full moon) during a lunar eclipse provides evidence that Earth is __________________________.
Curved

14. 4. Measurement of Gravity
b. The shorter the distance between two objects, the greater the gravitational force. Therefore a person or object that is closer to the center of Earth (the center of gravity) would weight more than when the person or object is farther from the center of gravity.

15. If Earth was a perfect sphere.
c. (1) If Earth is an “oblate spheroid”, where on the surface of Earth would a person be closer to the center of Earth?
_________________________
(2) Where on the surface of Earth would a person weigh the most?
d. Under what circumstance would a person weigh the same everywhere on Earth?
At the poles
At the poles
If Earth was a perfect sphere.

16. a sphere curved 5. Observation of North Star, Polaris
The altitude of Polaris changes as an observer moves north or south (in the Northern Hemisphere);
this is because Earth is _____________, and its surface is _____________________.
(Altitude is the height, measured in degrees that a heavenly body is above the horizon of the observer).
a sphere
curved

17. 1 2 3 4 Observer LATITUDE ALTITUDE of POLARIS 90 ° North 90 °
60 °
30 ° North
30 °
0 °
0 °

18. c. 60 90 30 Canada 60 ° N North Pole 90 ° N Alt. of Polaris 60 °
Altitude of Polaris = 90 ° 60 90
Equator 0°
Alt. of Polaris 0°
Atlanta 30 ° N
Alt. of Polaris 30 ° 30

19. Altitude of Polaris = Latitude
d. Summary:
Altitude of Polaris = Latitude
As latitude increases altitude of Polaris increases.
NORTH STAR- POLARIS
e. Locating the North Star

20. IV. Latitude and Longitude Latitude- Parallels- Equator-
North/South Pole-
The angular distance North or South of the equator.
Lines that measure latitude that never touch.
Reference line for 0° latitude. Midway between both poles.
Highest possible latitude, 90° North, 90° South
90°North
60° North Arctic Circle
30°North Tropic of Cancer
0° Equator
30°South Tropic of Capricorn
60° South Antarctic Circle
90°South

21. IV. Latitude and Longitude B. Longitude- Meridians- Prime Meridian-
International Date Line-
The angular distance East or West of the Prime Meridian.
Lines of longitude that connect from pole to pole.
Reference line for longitude 0°, that goes through Greenwich England.
Largest possible longitude, 180°

22. Location Latitude Longitude 1 2 3 4 5 120 ° West 30 ° North 45 ° South
75 ° East
0 °
135 ° West
135 ° East
45 ° North
70 ° South
165 ° West

23. Location Latitude Longitude 6 7 8 9 10 45 ° South 180° 45 ° North
75 ° West
70 ° North
0 °
15 ° South
15 ° East
20 ° South
45 ° West

24. North America South America Europe Asia Africa Australia Antarctica
CONTINENTS A B C D E F G
North America
South America
Europe
Asia
Africa
Australia
Antarctica

25. Oceans H I J K L
Atlantic
Pacific
Indian
Antarctic
Arctic

26. Right Hand Rule 6 AM D. Earth’s Time Zones
As Earth rotates on its axis, half of earth is facing the sun and is experiencing daylight; the other half is in darkness and is experiencing night.
2. When the sun is directly over a certain meridian, it is 12 noon at any location at or near that meridian.
12 Noon
12 AM
6 PM
Right Hand Rule

27. Rate of Earth’s rotation ?
3. Think:
Earth is a sphere/degrees in a circle =
Time/ Hours to make one complete rotation =
4. a. Number of time zones on Earth =
b. Approximate width of each time zone =
360° =
15°/hr
24 hours
24 time zones
15°

28. International Date line- Day change
5. a. If it is Wednesday, and you cross the International Date Line going west, it would then be _________________
b. It is Tuesday, and you cross the International Date Line while traveling east, it would then be _________________
International Date line- Day change
Tuesday
Wednesday

29. 6.
How many time zones are there in the continental U.S.?
_________________
b. Is it earlier or later in California than New York?
c. If it is 8:00 EST, what time is it in PST?
d. It is 6:00 MST, what time is it in EST?
____________________
4 time zones
Earlier
5:00
8:00