Introduction to World Geography
Mr. Healey
Equator
Imaginary line that divides the earth into
northern and southern hemispheres.
It is expressed as 0° Latitude.
Northern
Hemisphere
Equator
Southern
Hemisphere
Prime Meridian
Imaginary line that divides the earth into
eastern and western hemispheres.
Greenwich, England = 0° Longitude.
Prime Meridian
Eastern
Hemisphere
Western
Hemisphere
Latitude Lines (Parallels)
Used to locate places north or south of the
equator
Lines run parallel to the equator
Total of 180 lines of latitude
90° North
90° South
Longitude Lines (Meridians)
Used to locate places east or west of the Prime
Meridian.
Lines run from the North Pole to the South Pole.
Total of 360 lines of longitude
180° East
180° West
Longitude Lines and Time
The distance between lines of latitude and longitude is
approximately 70 miles.
As the Earth revolves around the sun, different parts of the
Earth are experiencing different times of day at the same time.
For example, if it is twelve noon here, can the sun still be
shining half-way around the world from our location?
Of course the answer is NO! As the Earth rotates, both sides of
the globe cannot be facing the sun at the same time.
QUESTION: How do we tell what time it is around the world?
ANSWER: We use lines of longitude to assist us.
Lines of longitude can also mark the hours of
the day as the Earth rotates.
Every 15° east or west is equal to one hour.
If it is 12 noon at the Prime Meridian, what is the time at the other
meridians?
North Pole
O Degrees
30 W
15 W
(Prime Meridian)
90 W
South Pole
15 E
30 E
90 E
Major Latitude Lines
Equator = 0°
Tropic of Cancer = 23.5° North
Arctic Circle = 66.5° North
North Pole = 90° North
Tropic of Capricorn = 23.5° South
Antarctic Circle = 66.5° South
South Pole = 90° South
Major Latitude Lines
North Pole 90° North
Arctic Circle 66.5° North
Tropic of Cancer 23.5° North
EQUATOR 0°
Tropic of Capricorn 23.5° South
Antarctic Circle 66.5° South
South Pole 90° South
Major longitude Lines
Prime Meridian = 0°
International Date Line = 180°
Seasons
As the Earth revolves around the Sun, it is tilted
at 23.5° angle.
Because of the Earth’s revolution and its tilt,
different parts of the Earth receive the direct
rays of the sun for more hours of the day at
certain times of the year.
This causes the changing of the seasons on the
Earth.
Vernal (Spring) Equinox
Occurs when the sun is directly over the
Equator. (March 21st ).
Equal amount of day and night during a 24hour period.
Earth is tilted at 23.5 degrees
North Pole 90° N
Sun’s direct rays
strike the Equator
Equator
South Pole 90° S
Summer Solstice
Occurs when the sun is directly over the Tropic of Cancer
(June 21st).
Marks the longest day of the year in the northern
hemisphere.
New York City sees approx. 15 hours of light and 9 hours of
dark.
Sunrise = 5:25am
Northern Hemisphere facing sun’s direct rays
Sunset = 8:30pm
North Pole 90° N
Sun’s direct rays strike
the Tropic of Cancer
Tropic of Cancer
23.5° North
South Pole 90° S
Autumnal Equinox
Occurs when the sun is again directly over the
Equator (Sept. 23rd).
Equal amount of day and night during a 24-hour
period.
Earth is tilted at 23.5 degrees
North Pole 90° N
Sun’s direct rays
strike the Equator
Equator
South Pole 90° S
Winter Solstice
Occurs when the sun is directly over the Tropic of
Capricorn (December 21st).
Marks the shortest day of the year in the northern
hemisphere.
New York City sees the reverse in hours of day and
night from the summer solstice.
Northern Hemisphere tilted away from sun
North Pole 90° N
Sun’s direct rays strike
the Tropic of Capricorn
Tropic of
Capricorn 23.5°
South
South Pole 90° S
Aphelion
The point at which the earth is farthest from the sun during its orbit.
Occurs around July 3 when the earth is 94.5 million miles away.
Perihelion
The point at which the earth is closest to the sun during its orbit.
Occurs around January 4 when the earth is 91.4 million miles away.