Topic 1: Introduction To Planet Earth
 What
 Why
is Physical Geography?
is Physical geography Important?
 Introduction
to Planet Earth
- Earth in the Universe
- The Solar System
 Shape
and Size of Planet Earth
Topic 1: Introduction To Planet Earth
 The
Geographic Grid System
- Latitude and Longitude
- Longitude and Time
- International Dateline
 Movements
of the Earth
- Earth’s Rotation and Effects
- Earth’s Revolution and Effects
What is Geography
 Geography
is the study of the spatial
and temporal distributions of:
- all physical elements and
- all human elements
on the earth surface
Physical & Human Elements on Earth Surface
Physical Elements
Human Elements
Rocks
Population
Minerals
Settlements
Landforms Soils
Economic Activities
Soils
Transportation networks
Fauna (animals)
Recreational Activities
Flora (plants)
Religion
Climate
Languages
Water
Political Systems, etc
What is Geography?
 It
involves a clear understanding of:
- why physical & human elements are
located where they are
- how they interact in space & time to
give character to our landscape
-
how interactions among places
organize the earth surface into spatial
forms and patterns
What is Geography?
- the processes responsible for and
continually changing the spatial
distributions and patterns of all
geographic elements on earth
 Hence,
geographers are interested in:
- "where" information or
- place or location information and
 - often associated with memorizing
“place names”
What is Geography?

Physical geographers are interested in the
distribution of all the physical elements broadly
grouped into four spheres:
- Atmosphere
- Hydrosphere
- Biosphere
- Lithosphere, & labeled as Physical Geography

Physical Geography is natural science with a
focus on the study of climate, soil, landforms,
vegetation (i.e., biogeography)
What is Geography?
 Today,
the increasing role of human
actions in changing the physical
environment is becoming critical
Why is Physical Geography
Important?
 The
course meets SIUE general
education requirements
 Improves
our understanding of the
physical environment and how it works
 He
us to understand that the physical
environment is a resource as well as a
source of natural hazards
Why is Physical Geography
Important?
 Improves
our landscape appreciation
and awareness
A
useful guide to environmental
planning and management
Earth in the Universe
 The universe is organized into clusters of
stars called Galaxies
 We
have billions of galaxies in the universe
 There
are over 100 billions of stars in some
galaxies
 Our
sun is one of such stars in our galaxy
called Milky Way Galaxy
Milky Way Galaxy: Thin Disk with a Central
Bulge

The Universe is about 12-15 billion years old
The Milky Way Galaxy
Earth in the Universe
 The
Milky Way is a spiral galaxy, diskshaped with a central bulge and about
100,000 light years across
 One
light-year is equal to 5.875trillion
miles or 9.4 trillion kilometers per year
 Our
sun is located on one of the spiral
arms called Orion arm
The Solar System
The Solar System Consists of:
 The sun (center of the solar system) and eight
planets

Four inner planets of the solar system are
called terrestrial planets: (Mercury,
Venus, Earth and Mars)
The Solar System
The Solar System Consists of:

>10,000 asteroids (asteroid belt between Mars
and Jupiter)
An Asteroid With Impact Craters
The Solar System
The Solar System Consists of:
 meteorites (pieces of rocks and minerals frozen
in gases)

Hale-Bopp Comet seen (1997) with long
glowing tail due to ice vaporization
The Solar System
The Solar System Consists of:
 meteorites (pieces of rocks and minerals
frozen in gases)

Hale-Bopp Comet seen (1997) with long
glowing tail due to ice vaporization

natural satellites or moons (>64 moons)

all the planets formed same time from same
general materials and move counterclockwise
Solar Systems


Pluto is no longer regarded as a planet of the solar
system
Solar Systems

Pluto is not part of our solar system because of:
- its unique oblique orbital plane and
-
its relatively higher density, given its location
Solar Systems

This is the current composition of the solar
system

All planets orbit in the same plane as the sun’s
Solar Systems

The Nebula theory is the most accepted
explanation of how the solar system is formed
 According to the Nebular hypothesis:
-
solar system evolved from rotating cloud of
dust and gases called nebula
-
nebula contained mainly hydrogen and
helium produced by the Big Bang
-
nebula began to contract at about 5 billion
yrs ago
Solar Systems

According to the Nebular hypothesis:
-
nebula became flat and disk-shaped with
the protosun at the center
-
inner planets began to develop from
condensed rocky and metallic clumps with
high melting point
-
strong solar winds removed the lighter
gases like hydrogen and helium from the
inner planets
Solar Systems

According to the Nebular hypothesis:
-
larger outer planets began to form from the
lighter gases with a high percentage of
ices or frozen gases – water, carbon dioxide,
ammonia, and methane
Glowing nebular clouds of gases and dust
particles become concentrated to form stars
Nebula contracted into a rotating
disk and heated up as gravitational
energy converts into heat energy
Gravitational collapse of nebula
causing its inward contraction
Cooling nebula condenses
to form tiny rocky and
metallic solid particles
Collision of dust-size particles join to
form asteroids and accrete to form the
planets
Features of Terrestrial Planets

Terrestrial planets: Mercury, Venus, Earth &
Mars

Composed of minerals and rocky materials

more dense (>3gm/cm3)

Less oblate in shape (more nearly spherical)

Slower in rotation and Smaller in size
Common Features of The Planets
Planets
Rotation Time
(Days)
Equatorial
Diameter (km)
Mean Density
(g/sq. cm)
TERRESTRIAL PLANETS
Mercury
58.7
4,880
5.43
Venus
243
12,104
5.24
Earth
1
12,760
5.52
Mars
1.03
6,787
3.98
Jupiter
0.41
142,796
1.33
Saturn
0.43
120,660
0.69
Uranus
0.72
51,200
1.27
Neptune
0.67
49,500
1.76
6.39
2,300
2.03
JOVIAN PLANETS
OTHER PLANETS
Pluto
Features of Jovian Planets

consist of: Jupiter, Saturn, Uranus
Neptune

much larger in size

composed entirely of gases and less dense

much more oblate and rotate more rapidly

dense and turbulent atmospheres
Shape of Planet Earth

Ancient Greek Scholars always believed that
the earth is spherical in shape

In 200 B.C., Eratosthene estimated the
circumference of the earth

The spherical shape of the earth is supported
by:
- lunar eclipse
- circular horizon around the earth
- satellite photographs of the earth
- variations in the force of gravity, etc
Shape of Planet Earth
 The spherical shape of the earth is
caused by the gravitational attraction of
earth’s materials
 But
the centrifugal force of earth’s
rotation has distorted the shape from a
perfect sphere
 Hence,
the earth bulges at the equator
and flattens at the poles, a shape
described as oblate spheroid
Shape of Planet Earth
 The
oblate spheroidal shape is
supported by:
- a polar diameter that is shorter
than the equatorial diameter by 27
miles
- a relatively lower value of gravity at
the equator and a higher value at
the poles
Oblate Spheroidal Shape of the Earth
Eratosthene’s Measurement of
Earth’s Circumference
 Eratosthene
made his measurements in
Egypt
 Based
his measurement on the geometric
properties of a sphere
 Measured
an arc of a circle around the
earth by measuring the distance between
Alexandria and Syene (5000 stadia)
Eratosthene’s Measurement of
Earth’s Circumference
 He
measured the angle subtended by the
arc at the center of the earth by using:
- solar elevations at Alexandria & Syene
taken on summer solstice at noon
- the properties of parallel lines
elevation at Alexandria was 7.2o
and vertical (90o) at Syene on the Tropic
of Cancer (why?)
 Solar
Eratosthene’s Measurement of
Earth’s Circumference

Found the angle subtended by the arc at the
center of the earth to be 7.2o

By extrapolation, he calculated earth
circumference to be 250,000 stadia or 43,000 km
(if one Attic stadium measured 184 m or 407 ft)

Earth’s actual circumference is 40,000km or
25,000 miles
Size of Planet Earth
 Earth’s polar diameter: 7900 mi
(12,714 km)
 Equatorial diameter:
7927 mi
(12,756 km)
 Polar circumference:
24,819 mi
(39,943 km)
 Equatorial circumference 24,902 mi
(40,0076 km)
 Equatorial diameter is longer by 27mi
or 42 km
The Geographic Grid System
 The
geographic grid system is also
referred to as the Graticule
 It
consists of east-west lines (latitudes)
and north-south lines (longitudes)
 It
is designed to intersect at right angles
to permit precise location of points on
the globe
The Geographic Grid System
The Geographic Grid System
 The
natural reference points for location
measurements purposes include:
- North Pole
- South Pole
- equator
 The
primary purpose of the grid system
is for the precise location of points
Locating Points Using a Grid system
The Geographic Grid: Latitude
 Latitudes
are also called parallels of
latitude because they don’t meet
 it
is a true east-west line
a
line of latitude goes round the globe to
form a full circle called circle of latitude
 circles
of latitude are progressively smaller
towards the poles where it is a point
Parallel or Circle of Latitudes
The Geographic Grid: Latitude
 largest circle of latitude is midway
between the poles called the equator
 the
Equator is a Great Circle because it
divides the globe into 2 equal parts
 all
other circles of latitude are small
circles
A
Great Circle is always the shortest route
between 2 points and useful for navigation
The Geographic Grid: Latitude
 Latitudes
are measured in angular
degrees north or south of the equator
latitudes have values between 0o
and 90o N or S of the equator
 Hence
 One
degree of latitude is about 111 km
(69 mi) space apart
Length of Degrees of Latitude & Longitude
Latitudes
mi
km
0o
68.703 110.567
Length of 1o of longitude
measured along a parallel
mi
km
69.172
111.321
20o
68.789 110.705
65.026
104.649
40o
68.998 111.042
53.063
85.396
60o
69.235 111.423
34.674
55.802
80o
69.387 111.668
12.051
19.394
90o
69.407 111.699
0
0
The Geographic Grid: Latitude
 Calculate the distance (in miles) between
St. Louis, MO (39o & 90oW) and New
Orleans LA (30o N & 90oW) as the crow
flies (Hint: a degree of latitude is spaced
about 111 km (69 mi) space apart)
 First
determine how many degrees of
latitudes separate the two cities
 Answer:
_______(km)
The Geographic Grid: Important
Latitudes
 important
-
latitudes:
Arctic Circle (66½o N)
Antarctic Circle, (66½o S)
Tropic of Cancer (23½o N)
Tropic of Capricorn (23½o S)
North Pole (90oN)
South Pole (90o S)
Latitude of Edwardsville (38o 49’ N)
The Geographic Grid: Important
Latitudes
The Geographic Grid: Longitude
 Longitudes
are also called meridians
(mid-day lines) because all places on the
same longitude have the same mid-day
 It
runs north-south from pole-to-pole and
crosses all latitudes at right angles
 It
is measured in angular degrees east or
west of the Prime Meridian or Greenwich
Meridian (i.e., Long. 0o)
Meridians
How to Determine the Longitude of a Place:
Los Angeles
The Geographic Grid: Longitude
-
Values
are between 0o & 180o E or W
- lines of longitude converge at the poles
- each meridian is half a Great Circle &
two opposite meridians form a Great
Circle (0o & 180o or 60oE & 120oW)
- Longitude & latitude determine the
precise location of a place
Lines of Longitudes Converging at the Poles
Longitude and Time
- Before 1884, communities set their
local clock to its local solar noon
- keeping appointment was difficult to
coordinate because each community
kept different local time
- in 1884, 24 standard time zones (each
15 degrees of longitude wide) were
established
A Sundial: Oldest Time Measuring Device
(Used in Babylon in 2,000 B.C.)
Gnomon
Longitude and Time
- local solar time of the Prime Meridian
was chosen as the standard for the
entire system
- it became the center of a time zone
that extends 7.5 degrees of longitude
to the west and east of it
- 23 other standard meridians (multiples
of 15o) were established
Longitude and Time
- Boundary of each standard time zone
has been adjusted to follow state or
administrative boundaries
- United States has six time zones,
whereas, the continental United States
has four
- International Date Line (IDL) follows
long. 180o
The Standard Time Zones
United States Six Standard Time Zones
Standard Time Zones
Standard Meridians
Eastern Standard Time
75oW
Central Standard Time
90oW
Mountain Standard Time
105oW
Pacific Standard Time
120oW
Alaska-Hawaii standard Time
150oW
Bering Strait standard Time
165oW
The Standard Time Zones For The
United States
Longitude and Time
- places to the immediate west or east of
IDL have 24 hours time difference
- Cross the IDL from east to west
GAIN a day
- Cross from west to east LOSE a day
International Date Line
Earth’s Rotation
 Rotation
is the movement of the earth
around it’s axis as:
- it points towards Polaris
- and inclined at 66½o from the ecliptic
plane
 Rotation
is from west to east as observed
from the side
 Or
counterclockwise as observed from
the North Pole
The Plane of the Ecliptic
Earth’s Rotation Axis
Earth’s Rotation
Earth’s Rotation
 All
points on the earth surface move in a
circle around the axis (except the pole)
during rotation
 The
circle of rotation defines the latitude
of the point
 The
earth completes one full rotation
around its axis in 24 hours (one solar day)
Earth’s Rotation
 The
earth completes one full rotation
with respect to the star in 23 hours 56
minutes and 4.099 seconds (sidereal day)
 The
maximum speed of earth’s rotation
is 465 m/sec or 1040 mi/hr or 1670km/hr
at the equator
 The
speed is 0 mi/hr or 0 km/hr at the
poles
Speed of Rotation at selected Latitudes
Latitudes
Miles per Hour
Kilometers per Hour
0o
1037.6
1669.9
20o
975.4
1569.7
40o
795.9
1280.9
60o
520.1
837.0
80o
180.8
291.0
90o
0
0
Effects of Earth’s Rotation
 Earth’s
rotation axis defines the North
Pole and South Pole
 The
circle of rotation of a point defines
its circle of latitude
 Rotation
in and out of sunlight causes:
- day and night
- diurnal variations in temperature,
humidity, and wind movements
Effects of Earth’s Rotation

Rotation brings any point on the earth surface
in and out of the increasing and decreasing
gravitational pulls of the moon and sun to cause
the rise and fall of tides or water levels

Causes the oblate speroidal shape of the earth

Rotation in the same direction causes apparent
deflection of the flow path of air and water
bodies called coriolis effect
Earth’s Rotation Causing Rise and Fall of Tides
Effects of Earth’s Rotation
 Coriolis
effect causes the flow path of
air and water to be deflected to the
right in the northern hemisphere and
to the right in the southern hemisphere
Coriolis Effect
Earth’s Revolution
 Revolution is earth’s movement around
the sun
 Path
of earth’s revolution is called the
orbit
 The
orbit is elliptical in shape such that:
- on January 3, the earth is at the
Perihelion or near the sun position
(or 147.5 million km or 91.5 million
mi from the sun)
Path Followed By the Earth During
Revolution (Elliptical Orbit)
July 4
Jan. 3
Earth’s Revolution
-
On July 4, the earth is at the aphelion
(far away) position on the orbit (or
152.5 million km or 94.5 million miles
from the sun
 The
earth moves in a counterclockwise
direction and completes one full
revolution in 365¼ days (Tropical Year)
Earth’s Revolution
 The
¼ day adds up to one full day every
four years, to give a leap year (366 days)
 Earth’s
axis points always at the Polaris
during revolution (Polarity or Parallelism
of the earth’s axis)
Polarity or Parallelism of Earth’s Axis During
Revolution
Effects of Earth’s Revolution
 Defines
the northernmost limit of
overhead sun at noon as the Tropic of
Cancer (lat. 23½o N)
 Defines
the southernmost limit of
overhead sun at noon as the Tropic of
Capricorn (lat. 23½o S)
 Defines
the Tropics as where the sun is
overhead (subsolar point) twice a year
Effects of Earth’s Revolution
 Solstice,
which is the day of year the sun is
overhead at the Tropic of Cancer and the
Tropic of Capricorn
 Summer
Solstice is the day the sun is
overhead at the Tropic of Cancer in the
northern hemisphere
 Winter
Solstice is the day the sun is
overhead at the Tropic of Capricorn
Effects of Earth’s Revolution
 Defines
the Equinoxes:
- Vernal (Spring) Equinox
- Autumnal (Fall) Equinox
 Determines
 Causes
-
the Length of Daylight
the four seasons:
Summer Season
Winter Season
Spring Season
Fall Season
Effects of Earth’s Revolution
 Determines
the amount of solar energy
received at a place
Conditions at Equinox
(March 20 and September 22)
 Earth
appears to stand upright in
relation to the sun
 Hence,
the circle of illumination passes
through the poles
 The
sun is overhead (subsolar point) at
the Equator
Conditions at Equinox
(March 20 and September 22)
 All
places experience 12 hours of daylight
and 12 hours of darkness
 The
March Equinox is called Vernal
(Spring) Equinox
 The
September Equinox is called
Autumnal (Fall) Equinox
Sun-Earth Relationship On Equinoxes
Conditions at Summer Solstice in
N.H. (June 21)
 Northern
hemisphere leans towards the
sun
 Sun
is overhead (subsolar point) at the
Tropic of Cancer
 All
places north of the Tropic of Cancer
record their highest angle of the sun at
noon
Sun-Earth Relationship During
Summer Solstice in N.H.
Conditions at Summer Solstice in
N.H. (June 21)
 The
circle of illumination cuts the polar
circles tangentially
 There
is 24 hours of continuous sunlight
in all areas north of the Arctic Circle (lat.
66½o N)
 There
is 24 hours of continuous darkness
in all areas south of the Antarctic
Circle(lat. 66½o S)
Conditions at Summer Solstice in
N.H. (June 21)
 The
Longest day of the year recorded
in N.H. and longest night in S.H.
 It
is winter solstice in S.H.
 Equator
receives 12 hours of daylight
Conditions at Winter Solstice in
N.H. (December 21)
 Northern
hemisphere leans away from
the sun
 The
sun is overhead at noon (subsolar
point) at the Tropic of Capricorn
 Highest
sun angle recorded in all places
south of the Tropic of Capricorn
Sun-Earth Relationship During Winter
Solstice (December 21) in N.H.
Conditions at Winter Solstice in
N.H. (December 21)
 Circle
of illumination touches Arctic
Circle on near side of Earth
 Circle
of illumination touches Antarctic
Circle on the far side of Earth
 24
hours of continuous sunlight in areas
south of the Antarctic Circle
Conditions at Winter Solstice in
N.H. (December 21)
 24
hours of continuous darkness in
areas north of the Arctic Circle
 Day
length increases with increasing
latitude in Northern Hemisphere
 Day
length decreases with increasing
latitude in Southern Hemisphere
Conditions at Winter Solstice in
N.H. (December 21)
 Summer
solstice in Southern
Hemisphere
 Equator
receives 12 hours of daylight
The Four Seasons
 Four
season initiated at the solstices and
equinoxes
 Summer
season initiated by summer
solstice because of the very high solar
altitude and its maximum solar energy
 Fall
season initiated by autumnal equinox
because of declining solar altitude and
solar energy
The Four Seasons
 Winter
season is initiated by winter
solstice because of the further
decline in solar altitude and solar
energy to their lowest levels
 Spring
season is initiated by vernal
equinox because solar altitude and
solar energy are beginning to rise
again
Polarity or Parallelism of Earth’s Axis During
Revolution
The March of the Seasons
Length of Daylight
 12
hours day and 12 hours night at the
equinoxes
 Longest
day of the year occurs on
summer solstice
 24
hours of daylight beyond the polar
circles on summer solstices
Length of Daylight
 24
hours of darkness beyond the
polar circles on winter solstice
 Shortest
day of the year occurs on
winter solstice
Day Length At June Solstice, N.H.
Latitudes
Day Length
Sun Angle at Noon
90o N
24hr
23.5o
80o N
24hr
33.5o
70o N
24hr
43.5o
60o N
18 hr 53 min
53.5o
50o N
16 hr 23 min
63.5o
40o N
15 hr 01 min
73.5o
10o N
12 hr 23 min
76.5o
0o N
12 hr o7 min
66.5o
Day Length At June Solstice, S.H.
Latitudes
Day Length
Sun Angle at Noon
10o S
11 hr 32 min
56.5o
20o S
10 hr 55 min
46.5o
30o S
10 hr 12 min
36.5o
40o S
9 hr 20 min
26.5o
50o S
8 hr 04 min
16.5o
60o S
5 hr 52 min
6.5o
70o S
0
0
90o S
0
0
Analemma Shows the Latitude of the Vertical Rays of the
Noon Sun (Declination of the Sun) for Every Day of the Year
The Analemma: Used to Determine Solar
Altitude
 What
is the declination of the sun on
May 15 or February 30?
 Answer: Lat. 18oN or Lat. ___o S
 Solar
 Arc
Altitude = 90o – Arc Distance
distance is the number of degrees of
latitude between the location in
question and the declination of the sun
The Analemma: Used to Determine
Solar Altitude

Arc distance if location in question is in the
same hemisphere as the declination of the sun:
- subtract the smaller from the larger
latitude

Arc distance if location in question is in the
different hemisphere from the declination of
the sun:
- add both latitudes together
Bonus Assignment

Calculate the solar altitude at Edwardsville
on the following dates using the analemma:
- March 20
- June 21
- September 23
- December 21

Is it true that the angle of sun at noon is
highest on summer solstice?

When is the angle of the sun at noon lowest?
Review Questions
Topic One Review Questions
1) Which term properly describes the shape of
Earth?
A. Perfect Sphere
B. Perfect Ellipse
C. Perfect Spheroid
D. Oblate Ellipse
E. Oblate Spheroid
Figure 1-7
1) Which term properly describes the shape of
Earth?
A. Perfect Sphere
B. Perfect Ellipse
C. Perfect Spheroid
D. Oblate Ellipse
E. Oblate Spheroid
Explanation: The diameter of Earth between
the poles is shorter than the diameter of Earth
that intersects the equatorial plane. The shape must be
an oblate spheroid.
Figure 1-7
2) The South Pole is nearest the Sun during which of
these events?
A. March Equinox
B. September Equinox
C. December Solstice
D. June Solstice
E. Solar Eclipse
2) The South Pole is nearest the Sun during which of
these events?
A. March Equinox
B. September Equinox
C. December Solstice
D. June Solstice
E. Solar Eclipse
Figure 1-19
Explanation: During the December Solstice, the Southern Hemisphere is directed
towards the Sun. As a result, the South Pole is nearest the Sun during
the December Solstice.
3) If Earth rotated at one-half its current rotational
speed, which of the following would be true?
A. Months would last longer than 31 days
B. Years would be shorter than 365 ¼ days
C. Days would be exactly 24 hours
D. Days would be exactly 12 hours
E. Days would be exactly 48 hours
Figure 1-9
3) If Earth rotated at one-half its current rotational
speed, which of the following would be true?
A. Months would last longer than 31 days
B. Years would be shorter than 365 ¼ days
C. Days would be exactly 24 hours
D. Days would be exactly 12 hours
E. Days would be exactly 48 hours
Explanation: Currently, one Earth rotation takes 24
hours to complete. If Earth’s rotation speed slowed
to one-half its current speed, it would take twice as
long for Earth to rotate.
So, it would take 48 hours.
Figure 1-9
4) Lines of longitude have the greatest distance
between each other at which of the following
location(s)?
A. Equator
B. North and South Pole
C. Tropic of Cancer
D. Tropic of Capricorn
E. International Date Line
Figure 1-17b
4) Lines of longitude have the greatest distance
between each other at which of the following
location(s)?
A. Equator
B. North and South Pole
C. Tropic of Cancer
D. Tropic of Capricorn
E. International Date Line
Explanation: Lines of longitude converge as you
approach the poles. Consequently, at the equator, the
lines have the greatest spacing, and their spacing
decreases as you approach each pole.
Figure 1-17b
5) If the time is 12:00 A.M. in Greenwich, England,
what time is it in New York City, New York (EST)?
A. 5:00 A.M.
B. 7:00 P.M.
C. 12:00 A.M.
D. 7:00 A.M.
E. 5:00 P.M.
Figure 1-25
5) If the time is 12:00 A.M. in Greenwich, England,
what time is it in New York City, New York (EST)?
A. 5:00 A.M.
B. 7:00 P.M.
C. 12:00 A.M.
D. 7:00 A.M.
E. 5:00 P.M.
Figure 1-25
Explanation: New York, New York is 5 hours behind the time in Greenwich, England
(GMT). As a result, if it is 12:00 A.M. in Greenwich, it is 12:00 – 5 hours = 7:00 P.M.
in New York, New York.
6) The Sun’s heating ability over Earth gets stronger when
A. the Sun’s rays strike Earth at an angle
less than 10°.
B. the Sun’s rays strike Earth
perpendicularly (at a 90° angle).
C. one moves north from the equator
during Northern Hemisphere winter.
D. The Sun’s rays strike Earth obliquely
(angle less than 90°).
E. the Sun is nearer Earth.
6) The Sun’s heating ability over Earth gets stronger when
A. the Sun’s rays strike Earth at an angle
less than 10°.
B. the Sun’s rays strike Earth
perpendicularly (at a 90° angle).
C. one moves north from the equator
during Northern Hemisphere winter.
D. The Sun’s rays strike Earth obliquely
(angle less than 90°).
E. the Sun is nearer Earth.
Figure 1-22c
Explanation: The amount of energy received from the Sun relates to the area over
which the area is received. Smaller areas receive a higher concentration of energy,
so they heat more. Perpendicular rays strike over the smallest area.
7) If you fly west from Australia to the United States,
departing on April 1, what day is it when you arrive
in the United States?
A. April 1
B. April 2
C. March 30
D. March 31
E. April 3
Figure 1-24
7) If you fly west from Australia to the United States,
departing on April 1, what day is it when you arrive
in the United States?
A. April 1
B. April 2
C. March 30
D. March 31
E. April 3
Figure 1-24
Explanation: If you fly west from Australia to the United States, you will never cross
the International Date Line. As a result, the day will remain April 1 through your entire
trip.
8) Northern Hemisphere summer solstice is experienced
on June 21. On this date, at solar noon, the Sun is
directly overhead at the
A. Equator.
B. Tropic of Cancer.
C. Tropic of Capricorn.
D. North Pole.
E. South Pole.
Figure 1-22b
8) Northern Hemisphere summer solstice is experienced
on June 21. On this date, at solar noon, the Sun is
directly overhead at the
A. Equator.
B. Tropic of Cancer.
C. Tropic of Capricorn.
D. North Pole.
E. South Pole.
Figure 1-22b
Explanation: During the June solstice, the Sun’s rays are directly overhead at the
latitude equal to the axial tilt of Earth, which corresponds to the Tropic of Cancer.
9) The speed of rotation of Earth’s surface is
highest at the
A. Equator.
B. Tropic of Cancer.
C. Tropic of Capricorn.
D. North Pole.
E. Arctic Circle.
Figure 1-18
9) The speed of rotation of Earth’s surface is
highest at the
A. Equator.
B. Tropic of Cancer.
C. Tropic of Capricorn.
D. North Pole.
E. Arctic Circle.
Figure 1-18
Explanation: At the equator, Earth must rotate the greatest distance in a
24-hour period. As a result, it must rotate faster at the equator than anywhere else.
10) The solid, inorganic portion of Earth is represented by
which of the four primary spheres?
A. Hydrosphere
B. Mesosphere
C. Atmosphere
D. Lithosphere
E. Biosphere
Figure 2-1
10) The solid, inorganic portion of Earth is represented by
which of the four primary spheres?
A. Hydrosphere
B. Mesosphere
C. Atmosphere
D. Lithosphere
E. Biosphere
Figure 2-1
Explanation: The lithosphere, or “stone” sphere, represents the solid parts of
Earth which are non-living (inorganic).