Models and Dimensions of Earth

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Models and Dimensions of Earth
I. Model
Simplified representation of an object or idea
A. Types and Examples of Models
PHYSICAL
1. __________________ - provides us with
information through our sense of sight.
Geographical Globe
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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
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Models and Dimensions of Earth
Mathematical model
3. __________________ - mathematical
relationships expressed by symbols, formulas, and
equations.
Equations
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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
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Models and Dimensions of Earth
Mental
5. __________________ - models that can only
exist in someones mind.
Water is made of 2 Hydrogen and 1 Oxygen molecules
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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
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greater
4. Earths equatorial circumference is
______________ than its polar circumference. a.
Equatorial circumference - ___________________ b.
Polar circumference - ______________________
24,900 miles
24,860 miles
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B. Causes of Earths 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
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Centrifugal Force
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
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(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
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• C. Evidence of Earths 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 earths
surface is ____________________.
Curved
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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
______________________________________.
Earths shadow
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b. As viewed from Earth
c. Earths shadow on the moon (full moon) during
a lunar eclipse provides evidence that Earth is
__________________________.
Curved
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4. Measurement of Gravity a. 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.
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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.
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• 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
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Observer LATITUDE ALTITUDE of POLARIS
1
2
3
4
90 North
90
60 North
60
30 North
30
0
0
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c.
Canada 60 N Alt. of Polaris 60
North Pole 90 N Altitude of Polaris 90
60
90
Equator 0 Alt. of Polaris 0
Atlanta 30 N Alt. of Polaris 30
0
30
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d. Summary
Altitude of Polaris Latitude
As latitude increases altitude of Polaris
increases.
NORTH STAR- POLARIS
e. Locating the North Star
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• 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
90North
60 North Arctic Circle
30North Tropic of Cancer
0 Equator
30South Tropic of Capricorn
60 South Antarctic Circle
90South
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• 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
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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
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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
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CONTINENTS
A
B
C
D
E
F
G
North America
South America
Europe
Asia
Africa
Australia
Antarctica
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Oceans
H
I
J
K
L
Atlantic
Pacific
Indian
Antarctic
Arctic
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6 AM

• D. Earths 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
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Rate of Earths 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
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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
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• 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 800 EST, what time is it in PST?
• _________________
• d. It is 600 MST, what time is it in EST?
• ____________________

4 time zones
Earlier
500
800