1. Geography as a Field of Learning
• Geography is a generalized discipline that
has the face of planet Earth as its focus.
• Rooted in the Greek words for “earth
description,” geography is the areal
differentiation of Earth’s surface.
Vocabulary
Antarctic Circle (p. 18) hydrosphere (p. 5) parallel (p. 11)
aphelion (p. 17) inclination of Earth’s axis (p. perihelion (p. 17)
Arctic Circle (p. 18) 17) physical geography (p. 1)
atmosphere (p. 5) International Date Line (p. plane of the ecliptic (p. 17)
biosphere (p. 5) 24) plane of the equator (p. 10)
circle of illumination (p. 18) international system of polarity (parallelism) of the
cryosphere (p. 5) measurement (SI) (p. 4) rotation axis (p. 18)
cultural geography (p. 1) June solstice (p. 18) prime meridian (p. 13)
December solstice (p. 19) latitude (p. 11) September equinox (p. 19)
equator (p. 10) lithosphere (p. 5) solar altitude (p. 18)
graticule (p. 11) longitude (p. 13) South Pole (p. 11)
great circle (p. 10) March equinox (p. 21) Tropic of Cancer (p. 18)
Greenwich Mean Time meridian (p. 13) Tropic of Capricorn (p. 19)
(GMT) North Pole (p. 11) Universal Time Coordinated
(p. 23) (UTC) (p. 23)
Geography as a Field of Learning
• The fundamental questions of geographic
inquiry are
– “Why is What Where?”
– “So What?”
1

2. Geography as a Field of Learning
• Geography’s basic characteristics are as follows:
– It looks at how things differ from place to place;
– It has no peculiar body of facts or objects it can call
wholly its own;
– It is a very broad field of inquiry and “borrows” its
objects of study from related disciplines;
– It is both a physical science and a social science
because it combines characteristics of both and can
be conceptualized as bridging the gap between the
two;
– It is interested in interrelationships, that is, examining
how various factors (both physical and cultural)
interrelate.
Geography as a Field of Learning
• Geography has two main
branches, Physical
Geography and Cultural
Geography:
– Physical Geography—
also known as
environmental geography,
it looks at those Earth
elements that are natural in
origin;
– Cultural Geography—also
known as human
geography, looks at
elements of human
endeavor.
Science and Geography
• The subject matter of this class is physical
geography.
• This class will focus on the Earth’s
physical elements, specifically:
– Their nature and characteristics, processes
involved in their development, their
distribution, and their interrelationships.
– This class will also explore the ways humans
have shaped the physical environment.
2

3. Science as a Field of Learning
• Science is described as a process that follows the
scientific method
• Observe phenomena that stimulates a question or
problem
• Offer an educated guess (hypothesis) about the answer
• Design an experiment to test the hypothesis
• Predict the outcome of the experiment
• Conduct the experiment and observe the outcome
• Draw conclusions and formulate rules based on the
experiment
Science as a Field of Learning
• Science does not always exactly fit this
methodology (i.e., data collection can be through
observation) and therefore science is best
thought of as a process for gaining knowledge
• Although the term “scientific proof” is used,
science does not actually prove things, but
rather eliminates alternative explanations.
• Science is based on disproving these alternative
explanations.
Science as a Field of Learning
• In science, theories represent the highest
order of understanding in a body of
information.
– Theories are logical and well-tested
explanations encompassing numerous facts
and observations.
3

4. Science as a Field of Learning
• The acceptance of theories is based on
evidence and not beliefs, nor the
pronouncements of “authorities.”
• Theories are revised based on new
observations and new evidence.
Science as a Field of Learning
• The scientific method is a self-correcting process
based on the refining of scientific knowledge
through peer review, which ensures that
research and conclusions meet rigorous
standards of scholarship.
• New scientific evidence may make scientists
change their minds, as well as lead to
disagreement within the scientific community,
but good science tends to take a cautious stance
toward conclusions that are drawn.
Science as a Field of Learning
• As such, scientists preface findings by stating that “the
evidence suggests,” or “the results most likely show.”
• This apparent circumspection can lead to a
misconception surrounding the validity of the scientific
method on the part of the general public.
• However, this very circumspection spurs scientists to
further seek knowledge and understanding.
• This class will present the fundamental of physical
geography as supported by scientific research and
evidence.
4

5. Numbers and Measurement
Systems
• This text offers measurements in both the
International System of Units, from the
French Système International (SI), and the
traditional (or English) system.
• SI is an extension of the metric system,
devised in the 1790s to provide simple and
scientific standard units.
– SI to English conversions may be found in
Tables 1-2 and 1-3, and in Appendix I.
Global Environmental Change
• Some characteristics of the global environment have
been in a perpetual state of change.
– The rate of change of some of these characteristics, however,
vary.
– Throughout this book, the topic of global environmental
change—both natural and human induced—will be addressed.
– Special attention is given to the accelerated effects of human
impact on the physical environment.
• This topic is integrated in the various chapters within the
text and is dealt with more overtly in short, box essays
titled “People and the Environment,” which focus on
human-environment interrelations.
The Environmental Spheres
Interacting spheres
• Earth’s surface is a complex
interface where four spheres
meet, and to some degree L
overlap and interact. These
four spheres provide important
organizing concepts for the B
systematic study of Earth’s
physical geography: A H
– Lithosphere
– Atmosphere Lithosphere
– Hydrosphere Litho, Greek for “stone”
• A subcomponent of the Atmosphere
hydrosphere that atmo, Greek for “air”
encompasses frozen water Hydrosphere
and snow is the cryosphere hydro, Greek for “water”
– Biosphere Biosphere
bio, Greek for “life”
5

6. The Solar System
• The geographer’s
concern with spatial
relationships properly
begins with the
relative location of
Earth in the universe.
– Solar system —
system of nine planets
(and moons, comets,
asteroids, meteors)
revolving around the
Sun; Earth is third.
The Solar System
• Sun—medium-sized star
and makes up more than
99 percent of the solar
system’s mass.
– The Sun is one of perhaps
100,000,000,000 stars in
the Milky Way Galaxy,
which is one of at least a
billion galaxies in the
universe.
The Solar System
• Earth’s planetary orbit lies in nearly the same plane as
all the other planets, except that of Pluto’s, which is
somewhat askew.
• Earth, like all the planets, revolves from west to east.
• Earth, like the Sun and most of the other planets, rotates
from west to east on its own axis.
6

7. The Solar System
• The terrestrial planets (the four inner planets —Mercury,
Venus, Earth, and Mars) are smaller, denser, and less
oblate and rotate on their axes more slowly than the
Jovian planets.
• Terrestrial planets are also comprised mainly of mineral
matter.
The Solar System
• The Jovian planets (the
four outer—Jupiter,
Saturn, Uranus, and
Neptune) are larger, more
massive, less dense and
more oblate than the
terrestrial planets.
• Jovian planets are
comprised mostly of gas.
– In more recent years, more
small-sized “Pluto-like”
dwarf planets and comets
have been discovered in
our solar system beyond
Neptune in the Kuiper Belt
The Size and Shape of Earth
• Frame of reference
determines whether one
looks at Earth as being
large or small.
• Earth is an oblate
spheroid rather than a
true sphere, though the Earth
variation from true
sphericity is exceedingly
minute, and so for most
purposes it can properly
be considered a sphere.
7

8. The Size and Shape of Earth
• Greek scholars as early
as six centuries B.C.
began believing Earth
was a sphere, with
several making
independent calculations
of its circumference that
were all close to reality.
• Eratosthenese did so by
observing the angle of the
Sun’s rays in Alexandria
and Syene on the same
day.
The Size and Shape of Earth
• Earth shape is affected
by two main facts:
– It bulges in midriff, because
of pliability of Earth’s
lithosphere;
– Its shape is therefore an
oblate spheroid.
– It has topographical
irregularities.
• In context of Earth’s full
dimensions, these
variations are minute.
Oblate Ellipsoid: the shape of Earth
The Geographic Grid
• A system of accurate
location is necessary to
pinpoint with
mathematical precision
the position of any spot
on Earth’s surface.
• The grid system is the
simplest technique, using
a network of intersecting
lines.
– Graticule—the grid system
for mapping Earth that
uses a network of parallels
and meridians (lines of
latitude and longitude).
8

9. • Geographic grid
– Graticule
– Parallels and meridians
– Fig. 1-18
The Geographic Grid
• Four Earth features
provide the set of
reference points essential
to establish the graticule
as an accurate locational
system:
• North Pole, South Pole,
rotation axis, and
equatorial plane (an
imaginary plane passing
through Earth halfway
between the poles and
perpendicular to rotation
axis).
The Geographic Grid
• Equator—the imaginary midline of Earth,
where the plane of the equator
intersects Earth’s surface. Is the parallel
of 0° latitude.
• Great Circle—the largest circle that can
be drawn on a sphere; it must pass
through the center of the sphere; it
represents the circumference and divides
surface into two equal halves or
hemispheres.
• Circle of Illumination—a great circle
that divides Earth between a light half
and a dark half.
• Small circle—a plane that cuts through
a sphere without passing through the
center.
• Graticule — The grid system of the
Earth consisting of lines of latitude and
longitude.
9

10. Latitude
• Latitude—the distance measured north
and south of the equator; it is an angular
measurement, so is expressed in
degrees, minutes, and seconds.
• Parallel—an imaginary line that
connects all points of the same latitude;
because they are imaginary, they are
unlimited in number.
• Seven parallels are particularly
significant:
– Equator, 0°
– North Pole, 90° N
– South Pole, 90° S
– Tropic of Cancer, 23.5° N
– Tropic of Capricorn, 23.5° S
– Arctic Circle, 66.5° N
– Antarctic Circle, 66.5° S
Latitude
• This is the angular
distance of a point north
or south of the equator.
• It increases from a
minimum of 0° at the
equator to a maximum of
90° at the north and the
south poles.
• Lines of latitude are
parallel to each other and
describe circles that
decrease in
circumference away from
the equator.
http://gea.zvne.fer.hr/module/module_b/module_b3.html
The Equator
• This is an imaginary line that divides the globe into equal
hemispheres.
• All parallels in the northern hemisphere are designated
as having north latitude.
• All parallels in the southern hemisphere are designated
as having southern latitude.
10

11. – Seven significant latitudes
– Fig. 1-13 and 14
Latitude
• Regions on Earth are
sometimes described as falling
within general bands of
latitude.
– Low latitude—generally
between the equator and 30º
N and S
– Midlatitude—between about
30-60º N and S
– High latitude—latitudes
greater than about 60º N and
S
– Equatorial—within a few
degrees of the equator
– Tropical—within the tropics
(between 23.5º N and 23.5º S)
– Subtropical—slightly poleward
of the tropics, generally
around 25–30º N and S
– Polar—within a few degrees of
the North or South Pole
Nautical Miles
• The actual length of one degree of latitude
varies according to where it is being
measured on Earth, because of the polar
flattening of Earth. Even with the variation,
each degree has a north–south length of
about 111 kilometers (69 miles).
– A nautical mile is defined by the distance
covered by one minute of latitude (1.15
statute miles or 1.85 kilometers).
11

12. Longitude
• Longitude—the distance
measured east and west on
Earth’s surface.
• Meridian—imaginary line of
longitude extending from pole to
pole (aligned in a north–south
direction), crossing all parallels
at right angles. (It’s not to be
confused with its other definition,
the sun’s highest point of the
day.)
– Meridians are not parallel to each
other, except where they cross at
the equator, where they are also
the furthest apart.
– They close together northward and
southward, converging at the poles.
Longitude
• This is the angular distance
of a point east or west of
the prime meridian located
at Greenwich, England.
• It increases to the west and
the east away from the
prime meridian (0°) to a
maximum of 180°.
• Lines of longitude are
farthest apart at the equator
and converge at the poles.
• All circles described by
meridians of longitude have
the same circumference.
http://gea.zvne.fer.hr/module/module_b/module_b3.html
Longitude
• Prime meridian—the
meridian passing
through the Royal
Observatory at
Greenwich, England.
Longitude is
measured from this
meridian both east
and west to a
maximum of 180°.
12

13. Earth-Sun Relations
• The functional
relationship
between Earth and
the Sun is vital
because life on
Earth is dependent
on solar energy.
Earth Movements
• Two basic Earth movements are critical for
continuously changing the geometric
perspective between the two:
1. Earth’s daily rotation on its axis;
2. Earth’s annual revolution around the Sun.
Earth’s Rotation on Its Axis
• Earth rotates toward the east on its axis, with one complete rotation
taking 24 hours.
• This eastward spin creates an illusion that the celestial bodies are
rising in the east and setting in the west.
• Although the speed of rotation varies from place to place, it is
constant in any given place, so humans do not experience a sense
of motion.
13

14. Earth’s Rotation on Its Axis
• This rotation has several striking effects on the physical
characteristics of Earth’s surface:
– There is an apparent deflection in the flow path of both air and
water; called the Coriolis effect, it deflects to the right in the
Northern Hemisphere and to the left in the Southern
Hemisphere.
– Any point of the surface will pass through the increasing and
decreasing gravitational pull of the Moon and the Sun.
– Most important of all, there is a diurnal (daily) alternation of light
and darkness, which in turn influences local temperatures,
humidity, and wind movements.
Earth’s Revolution around the Sun
• Tropical year—the time it takes Earth to
complete one revolution around the Sun;
for practical purposes it can be simplified
to 365.25 days.
• Earth’s revolution is an ellipse, which
varies the Earth–Sun distance.
Earth’s Revolution around the Sun
• The varying distance between Earth and the Sun
is not an important determinant of seasonal
temperature fluctuations.
– Perihelion—the point in an orbit that takes a planet
nearest to the Sun (for Earth, it is 147,166,480
kilometers or 91,455,000 miles, on January 3).
– Aphelion—the point in an orbit that takes a planet
furthest away from the Sun (for Earth, it is
152,171,500 kilometers or 94,555,000 miles, on July
4).
ANIMATIONS: animated movie Earth moving around sun showing the seasons
http://esminfo.prenhall.com/science/geoanimations/animations/01_EarthSun_E2.html
14

15. Inclination of Earth’s Axis
• Plane of the ecliptic—the
imaginary plane that passes
through the Sun and through
every point of Earth’s orbit
around the Sun.
– It is not perpendicular to
Earth’s rotation axis, which
allows for seasons to occur.
• Inclination of Earth’s axis—
the degree to which Earth’s
rotation axis is tilted (about
23.5˚ away from the
perpendicular).
Polarity of Earth’s Axis
• Polarity of the rotation
axis—also called
parallelism; occurs
because Earth’s axis
points toward Polaris, the
North Star, no matter
where Earth is in its orbit.
– The combination of
rotation, revolution,
inclination, and polarity
result in the seasonal
patterns experienced on
Earth.
The Annual March of the
Seasons
• During the year the changing relationship
of Earth to the Sun results in variations in
day length and in the angle at which the
Sun’s rays strike the surface of Earth.
– The latitude (or subsolar point or the
declination of the Sun) receiving the vertical
rays of the Sun.
– The solar altitude at different latitudes.
– The length of day at different latitudes.
15

16. – Figure 1-23: “Top view” of the march of the seasons.
June Solstice
• June Solstice—On or about June 21, the
North Pole is oriented most directly toward
the Sun.
– On this day the direct rays of the Sun at noon
strike perpendicular to the surface of the
Tropic of Cancer (23.5º N).
– The day lengths are longer in the Northern
Hemisphere on this day, and day lengths are
shorter in the Southern Hemisphere.
June Solstice
• Day length is equal on the equator because the circle of
illumination (the line dividing between half daylight and
nighttime on Earth) bisects the equator evenly.
• Arctic Circle—the parallel of 66.5° north latitude;
experiences 24 hours of light on this day.
• Antarctic Circle—the parallel of 66.5° south latitude;
experiences 24 hours of darkness on this day.
16

17. September Equinox (AKA autumnal
equinox)
• Occurs on or about
September 22 and all
latitudes experience 12
hours of day and 12
hours of night. This is
because all latitudes are
bisected evenly by the
circle of illumination.
• The equinoxes represent
the midpoints in the
shifting of direct rays of
the Sun between the
Tropic of Cancer and the
Tropic of Capricorn.
December Solstice
• December solstice – On or about December 21,
the South Pole is oriented most directly toward
the Sun.
– On this day the direct rays of the Sun at noon strike
perpendicular to the surface of the Tropic of
Capricorn (23.5º S).
– The day lengths are longer in the Southern
Hemisphere on this day, and day lengths are shorter
in the Northern Hemisphere.
December Solstice
• Day length is equal on
the equator because the
circle of illumination (the
line dividing between half
day light and nighttime on
Earth) bisects the equator
evenly.
– Arctic Circle—the parallel
of 66.5° north latitude;
experiences 24 hours of
darkness on this day.
– Antarctic Circle—the
parallel of 66.5° south
latitude; experiences 24
hours of light on this day.
17

18. March Equinox (AKA vernal
equinox)
• Occurs on or about March 20 and all latitudes
experience 12 hours of day and 12 hours of
night.
• This is because all latitudes are bisected evenly
by the circle of illumination.
– Figure 1-24: Earth-Sun relations on the solstices and equinoxes.
Seasonal Transitions
• Between the March equinox and
the June solstice the vertical rays
of the Sun migrate northward
until they reach the Tropic of
Cancer
• Latitudes north of the Tropic of
Cancer never experience the
vertical rays of the Sun, so the
June solstice marks the day
when they are at their highest
angle.
• After the June solstice the
vertical rays migrate south and
the situation is similar in the
Southern hemisphere between
the September equinox and the
December solstice, with the
Sun’s vertical rays reaching their
farthest point south at the Tropic
of Capricorn on December 21.
18

19. Subsolar Point
The latitude
of the
subsolar
point marks
the
sun’s
declination
which
changes
throughout
the
Year.
Day Length
• This shifting of the vertical rays of the Sun has a
direct influence on day length.
• Day length for a given hemisphere is longer as
the vertical rays of the Sun approach the tropics
within that hemisphere.
– Summary of Conditions on Equinoxes and Solstices
– Table 1-6
19

20. Day Length in the Arctic and the
Antarctic
• On the March equinox the Sun rises at the
North Pole and is continuously above the
horizon until the following equinox in
September.
• Constant daylight extends southward to
the Arctic Circle until the Sun’s vertical
rays reach their highest point on June 21.
Day Length in the Arctic and the
Antarctic
• Daylight begins to decrease northward toward
the North Pole until the September equinox.
• Between the September equinox and the March
equinox, the North Pole is in continual darkness.
• This overall pattern is reversed for the Southern
Hemisphere with increasing daylight between
the South Pole and the Antarctic Circle between
the September and the March equinox.
– Variations in Day Length and Sun Angle
• June Solstice (example)
– Table 1-7
20

21. Significance of Seasonal Patterns
• Both day length and the angle at which the
Sun’s rays strike Earth are principal
determinants of the amount of insolation
received at any particular latitude.
– Tropic latitudes are always warm/hot because
they always have high Sun angles and
consistent days close to 12 hours long.
– Polar regions are consistently cold because
they always have low sun angles.
Telling Time
• It was difficult to compare
time at different localities
when transportation was
limited to foot, horse, or
sailing vessel.
– Thus there were no
standard times; each
community set its own time
by correcting its clocks to
high noon (meridian, not to
be confused with meridian
of longitude).
Standard Time
• Use of local solar time
created increasing
problems with advent of
telegraph and railroad;
railroads stimulated
development of a
standardized time
system.
– An 1884 international
conference divided world
into 24 standard time
zones, each extending over
15° of longitude (also
determined prime
meridian).
21

22. – U.S. Time Zones
– Fig. 1-30
Standard Time
• Universal Time Coordinated
(UTC) — formerly Greenwich
mean time (GMT); a
standardized time system that
uses the local solar time of
Greenwich (prime) meridian as
its standard.
• In international waters, time
zone boundaries are defined
specifically and consistently;
• Over land areas, however,
zone boundaries vary,
sometimes undergoing great
manipulation for political and
economic convenience.
International Date Line
• International Date
Line—Along with
prime meridian,
provides the anchor
for the framework of
time zones.
– It is the line marking
where new days begin
and old days exit from
surface of Earth.
22

23. International Date Line
• Experiences a time
difference of an entire
day from one side of the
line to the other.
– Generally, the line falls on
the 180th meridian except
where it meanders to
ensure two island
groupings aren’t split apart
in their schedules (Aleutian
Islands and South Pacific
Islands).
International Dateline
Different days are observed on either side of the
International dateline (180th meridian = 15° X 12
hours), 12 hours difference from the Prime Meridian
International Date Line
• The extensive eastern displacement of the
date line in the central Pacific is due to the
widely scattered distribution of many of the
islands of the country of Kiribati
http://www.flickr.com/photos/telstar/433029904/
23

24. Daylight Saving Time
• Daylight Saving Time—
a practice by which
clocks are set forward by
an hour (or more) so as
to extend daylight into the
usual evening hours.
– Created originally in
Germany to help conserve
electricity for lighting.
– Became U.S. national
policy, though Arizona,
Hawaii, and part of Indiana
exempt themselves under
the Uniform Time Act.
– Now gaining international
acceptance.
01_T02.JPG
01_T03.JPG
24

25. 01_T04.JPG
01_T05.JPG
North America Map Terms
Lake Superior Mississippi River Brooks Range
Lake Huron Missouri River Rocky Mountains
Colorado River Sierra Nevada Mountains
Lake Michigan
Rio Grande Cascade Mountains
Lake Erie
Columbia River Appalachian Mountains
Lake Ontario Sierra Madre Occidental
Lake Winnipeg Sierra Madre Oriental
Lake Okeechobee Yucatan Peninsula
Great Bear Lake Great Plains
Great Slave Lake
Great Salt Lake
Gulf of St. Lawrence
Lago Nicaraugua
25