TOPIC 1.CONCEPT OF GEOGRAPHY
CONCEPT OF GEOGRAPHY
Meaning of Geography Phenomena
The Meaning of the Term Geography
Define the
term geography
The
term Geography is a combination of two Greek words: Geo and Graphein. Geo means
Earth and Graphein means to write, draw or describe. These two words together
form Geographia, which means to draw, write about or describe the Earth. These
meanings led to the development of the early definition of geography which
referred to description of the Earth by words, maps and statistics and included
both the physical earth and everything found on it such as plants, animals and
people. Therefore, Geography is the study of the distribution and
interrelationship of phenomena in relation to the Earth surface. Alternatively,Geography
can be described as the study of the Earth and its environment.
BRANCHES
OF GEOGRAPHY
There are two branches of Geography, namely:
1. Physical
Geography - mainly concerned with land formation processes, weather and
climate.
2. Human
and Economic Geography - involves the study of human activities on the Earth's
surface
Explain the inter-relationship between different geographical
phenomena
Physical
and human environments make up the two major geographical phenomena. The word
phenomena refers to facts or circumstances observed, or observable within
nature. Therefore, a geographical phenomenon is an occurrence or fact in the
geographical science. There exists an interrelationship between Geography and
other subjects; physical and human environments lead to geographical phenomenon
within the two types of environment. There are a variety of other geographical
phenomena that are interrelated, for example land resources provide soil that
support plants growth. Sun rays generate heat which lead to the evaporation of
water; water vapour forms clouds and eventually rain is formed. Climate
determines the types of plant and animal species that can survive in a
particular geographical area and influences human population distribution. On
the other hand, human activities can lead to modification of physical
environments, for example soil degradation, land reclamation and forest
conservation.
Components of the Solar System
Name the
Components of the Solar System
Below are the components that make up the solar system:
1. The Sun
2. Planets
3. Comets
4. Asteroids
5. Meteors;
and
6. Satellites
Importance of the Components of Solar System
Describe
the importance of the components of solar system
Components of the Solar System are important because:
1. They
produce heat and light potential for living organisms, for example the Sun
2. The
provide habitat for humans and other living organisms, for example the Earth
3. They
form craters which later become attractive sites for tourism activities, for
example meteors which produce meteorites that fall on the Earth's surface and
form craters
The Sun
The Sun
is a star.
Dimension of the Sun in Relation to Other Space Bodies
State the
dimension of the sun in relation to other space bodies
Dimension
of the Sun relative to other Space Bodies: The diameter of the sun is 1.4
million kilometers
Characteristics of the Sun
Describe
the characteristics of the sun
The Sun
is composed of approximately 75% Hydrogen, 23% Helium and 3% other elements.
Therefore, the elements which make up the Earth comprise only a small fraction
of the materials which form the Sun. These include Carbon, Iron, Oxygen,
Silicon etc. The Sun is the only source of light and heat that the planet
receives. The temperature of the Sun is estimated to be 20,000,000 degrees
Centigrade.
Solar Energy
The Term Solar Energy
Define the
term solar energy
Solar
energy is the heat and light produced from the Sun. The Sun is the source of
all energy on the Earth.
Different Uses of Solar Energy
Suggest
different uses of solar energy
Some of the different uses of Solar energy include:
1. Drying
clothes, meat, fish, fruits and grains
2. Photosynthesis
ingrowing plants to manufacture their own food
3. Generation
of electricity
4. Formation
of coal, gas and oil
5. Formation
of clouds and rainfall through evaporation of water caused by the heat of the
Sun
6. Giving
power to small radios and running small telephone systems by using silicon
solar batteries
7. Source
of Vitamin D to human bodies as the bodies absorb Sunlight
8. For
domestic purposes like cooking food, heating, water.
How the Use of Solar Energy Promotes Environmental Conservation
Explain
how the use of solar energy promotes environmental conservation
Utilization
of Solar energy in manufacturing industries reduces the production of chlorine
from industrially produced chlorofluorocarbon gases which cause depletion of
the ozone layer. The depletion of the ozone layer causes global warming. Solar
energy is used as an alternative source of energy, therefore reducing the
depletion of forests for charcoal and firewood.
How Solar Energy May Contribute to Emancipation of Women
Explain
how solar energy may contribute to emancipation of women
REDUCED
TIME BURDENS LEADING TO HIGHER-EARNING JOBS AND INCREASED ENTREPRENEURIAL
OPPORTUNITIES
Women
are often disproportionately responsible for household duties. This is
particularly acute in rural settings, where women spend considerable time on
tasks such as collecting firewood for basic cooking, heating, and lighting
needs. Access to energy allows for more efficient products—from those as basic
as a solar lantern to those as advanced as a washing machine. These products
can reduce the time burdens of domestic responsibilities and create time for
more productive, formal engagement in the local economy outside the home.
Empirical studies that have examined the impact of electrification on female
labor rates in developing country settings reinforce this hypothesis.
IMPROVED
BASELINE CONDITIONS LEADING TO GREATER ACCESS TO ECONOMIC OPPORTUNITIES
There
are a multitude of studies that demonstrate that improved access to electricity
improves baseline living conditions for women. These studies show improvements
to women’s health through cleaner indoor air; better nutrition and food safety
due to improved refrigeration; and improved health knowledge through better
access to mass media and more time to read.Interior and exterior lighting in
rural settings often means improved security for women, enabling greater
mobility to engage in productive activities under safe conditions. Anecdotal
evidence also shows improved education for girls as a result of access to
electricity, although most empirical studies do not show gender-differentiated
impacts.Improving these baseline conditions facilitates the ease by which women
can participate in the local economy: Healthy, safe, and informed individuals
are more apt to be productive.
The Planets
Planets in the Solar System
Locate the
planets in the solar system
Planets
are bodies that revolve around the Sun. Previously, they included Mercury,
Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto. Pluto does not
qualify to be a planet anymore as it is the smallest and does not revolve
around the Sun. Therefore, there are currently officially only eight planets in
our Solar System. The word 'Planet' originates from the Greek word 'Planetai'
which means 'Wandering' as the planets seem to move about in the Sky as
wandering stars. All planets revolve around the Sun in the same direction in
orbits that are elliptical and nearly in the same plane. The time taken to
complete an orbit depends on the distance from the Sun.
Relative Distance of Planets from the Earth
Show
relative distance of planets from the earth
How far
is each planet from Earth?
sually
when people ask this question, what they mean is "What is the distance
between the orbit of Earth and the orbit of each planet?" or "What is
the closest that each planet comes to Earth?" (These are essentially the
same question, because the planets can't get any closer than their orbital spacing
allows.) You can compute this in a rough way by assuming that the orbits are
circular and coplanar, and looking at the planet-to-Sun distance for each
planet. Since the distances are so large, we usually express them in
Astronomical Units (AU). (AnAUis the average distance from Earth to the Sun,
about 150 million kilometers or 93 million miles.) The table below lists the
distance of each planet from the Sun in AU.
Planet
|
Average distance from Sun in AU
|
Mercury
|
0.39
|
Venus
|
0.72
|
Earth
|
1.00
|
Mars
|
1.52
|
Jupiter
|
5.20
|
Saturn
|
9.58
|
Uranus
|
19.20
|
Neptune
|
30.05
|
Pluto (dwarf planet)
|
39.48
|
Other bodies in the
Solar System
Characteristics of Comets, Asteroids, Meteors and Satellites
Describe
the characteristics of comets, asteroids, meteors and satellites
Comets are
objects with leading heads and bright tails in the Sky. Sometimes they can be
seen at night. They are composed of ice crystals and fragments of solid matter.
They have highly elongated orbits around the Sun. They can be seen from the
Earth only when they come close to the Sun.
Asteroids are
solid heavenly bodies revolving around the Sun. They are mostly found between
the orbits of Mars and Jupiter. They are in thousands and the largest has
adiameter of just less than 800 Kilometres. The bodies can only be seen with a
telescope because they are very far away.
Meteors are
pieces of hard matter falling from outer Space. They can be seen when they come
close to the earth, at about 110-145 Kilometres, whereas as a result of
friction with the atmosphere, they become hot and usually disintegrated. They
fall on the Earth's surface as large boulders known as meteorites, or a meteor
if it is one. These bodies are made of Nickel, Iron and Silica.
Satellites are the
moons of the Planets and they can be defined as the small bodies which rotate
on their axis and revolve around the Sun. There are only seven (7) planets
which have satellites apart from 57 satellites in the Solar System. The number
of satellites depends on the size and nature of the planet.
Local Incidents Linked to Meteorites
Narrate
local incidents linked to meteorites
There
are two known meteorites in Tanzania. One is found in Mbozi district in Mbeya
region and the other is inMalampaka in the Kwimba district in Mwanza region.
These falling meteorites have resulted in the formation of craters.
The Earth
The
Earth is the only Planet among the planets in the Solar System that is known to
support life. (Pluto does not qualify as a planet any moreasit is the smallest
and does not revolve around the sun). The Earth is made up of the atmosphere
(air), hydrosphere (water bodies), the solid crust, molten materials and the
biosphere (living organism). Water bodies cover about three quarters of the
Earth's surface.
The Shape of the Earth and its Evidence
Describe
the shape of the earth and its evidence
There are many ways to prove that the earth is spherical. The
following are some of them:
1. CIRCUMNAVIGATION OF THE EARTH: The first voyage around
the world by Ferdinand Magellan and his crew, from 1519 to 1522, proved beyond
doubt that the earth is spherical. No traveller going round the world by land
or sea has ever encountered an abrupt edge, over which he would fall. Modern
air routes and ocean navigation are based on the assumption that the earth is
round.
2. THE CIRCULAR HORIZON: The
distant horizon viewed from the deck of a ship at sea, or from a cliff on land
is always and everywhere circular in shape. This circular horizon widens with
increasing altitude and could only be seen on a spherical body.
3. SHIP'S VISIBILITY: When a
ship appears over the distant horizon, the top of the mast is seen first before
the hull. In the same way, when it leaves habour, its disappearance over the
curved surface is equally gradual. If the earth were flat, the entire ship
would be seen or obscured all at once.
4. SUNRISE AND SUNSET: The sun
rises and sets at different times in different places. As the earth rotates
from west to east, places in the east see the sun earlier than those in the
west. If the earth were flat, the whole world would have sunrise and sunset at
the same time. But we know this is not so.
5. THE LUNAR ECLIPSE: The
shadow cast by the earth on the moon during a lunar eclipse is always circular.
It takes the outline of an arc of a circle. Only a sphere can cast such a
circular shadow.
6. PLANETARY BODIES ARE SPHERICAL: All observations from telescopes reveal that the planetary
bodies, the sun, moon, satellites and stars have circular outlines from
whichever angle you see them. They are strictly spheres. Earth, by analogy,
cannot be the only exception.
7. DRIVING POLES ON LEVEL GROUND ON A CURVED EARTH: Engineers when driving poles of equal length at regular
intervals on the ground have found they do not give a perfect horizontal level.
The centre pole normally projects slightly above the poles at either end
because of the curvature of the earth. Surveyors and field engineers therefore
have to make certain corrections for this inevitable curvature, i.e. 12.6 cm to
1 km.
8. SPACE PHOTOGRAPHS: Pictures
taken from high altitudes by rockets and satellites show clearly the curved
edge of the earth. This is perhaps the most convincing and the most up-to-date
proof of the earth's sphericity.
Earth's Movements
Types of Earth's Movements
Describe
the types of earth's movements
The Earth is in motion all the time. People cannot feel this
motion because they move with it like all other planets. There are two types of
movements of the earth, namely:
1. The rotation
of the Earth on its own axis
2. The
revolution of the Earth around the Sun
The Term Rotation
Describe
the term rotation
Rotation
refers to thespinning of a body on its axis. The earth rotates or spins on its
axis in an anti-clockwise direction, from West to East through 3600 in 24
hours. Thus for every 15 degrees of rotation, the earth takes one hour which is
the same as four minutes for every 1 degree.
An axis
is an imaginary line joining the N (North) and S (South) poles through the
center of the Earth.
Note: The
rotation of the earth is very rapid although it is difficult to feel itsmotion.
At the equator, every point of the earth's surface is traveling Eastwards at
about 1600 Km per hour. At latitude 40 degrees, the speed is about 1280 Km per
hr.
Evidence to Prove that the Earth Rotates
Give
evidence to prove that the earth rotates
Below is evidence that proves that the Earth rotates:
1. During
the night, stars appear to move across the sky from West to East
2. If one
travels in a fast moving vehicle, will notice trees and other objects on both
sides of the road are moving fast in the opposite direction
3. Rising
of the sun over the eastern horizon in the morning. This shows that the point
of observation, that is south, is moving by rotation from West to East
4. Day and
Night. During the Earth's rotations some regions face the sun while others do
not face it. Thise regions facing the sun experience day time whereas the
regions which are not facing the sun are in darkness (night). This proves that
the earth is rotating.
Significances of Earth's Rotation
Explain
the significances of earth's rotation
Alternation of day and night: Rotation of the earth causes the
sides of the earth which face the sun to experience daylight which is the day,
whereas the side that is not facing the sun at that time will be in darkness
(night).
1. The
occurrence of tides in the ocean caused by gravitational forces of the moon and
sun upon the rotation of the Earth
2. Deflection
of winds and ocean current
3. Time
difference between longitudes: The rotation is responsible for difference in
time between different places on Earth. It causes the difference of one hour in
every 15 degree interval between longitudes. The Earth rotates from West to
East and takes 24 hours to complete one rotation. The difference in time is 4
minutes for each degree of longitude
The Term Revolution
Define the
term revolution
Revolution
is defined as the movement of one body around another. The earth revolves
around the sun in an elliptical orbit. Due to the elliptical shape of the earth
orbit the sun is closer to the earth at one point of the year than at another.
The
farthest (maximum distance) position from the sun in orbit of the earth is
called aphelion while the nearest position of the earth to the Sun is known as
perihelion.
The Process of Revolution
Explain
the process of revolution
The
Earth is at aphelion each year on 4th July, when it is at the maximum distance
of 152 million kilometer form the sun. The earth is at perihelion each year on
3rd January when it is at the minimum distance of 147 million kilometers.
The
earth's revolution around the sun takes a year (365¼ days) therefore the speed
of revolution is about 29.6 kilometers per second. A normal year has only 365
days. The remaining fraction of ¼ day is added once in four years to make a
leap year of 366 days.
The Result of the Earth's Revolution Around the Sun
Describe
the result of the earth's revolution around the sun
The result of the Earth's Revolution around the Sun:
1. The
four seasons of the year; summer, autumn, winter and spring. A season is one of
the distinct period into which the year may be divided. In the northern
hemisphere the summer season months are May, June and July. Autumn months are
August, September and October, winter months are November, December and January
and spring months are February, March and April. In the southern hemisphere
summer season months are November, December and January. Autumn months are
February, March and April. Winter months are May, June and July and spring
months are August, September and October. Equinox refers to the period when the
sun is overhead at the equator.
2. Change
in the position of the midday sun at different times of the year. As the earth
revolves around the sun its position changes and makes it appear as if it is
the sun moving.
3. Varying
lengths of the day and night at different times of the year. The axis of the
earth is inclined to its elliptical plane at a certain angle of 66.5 degrees.
If the axis of the earth were vertical, the sun rays would be overhead at the
Equator, thus all places on the earth would always experience 12 hours of
daylight and 12 hours of night
The Importance of the
Parallels and Meridians
The Parallels and Meridians
Define the
parallels and meridians
Latitude
refers to the angular distance North or South of the equator measured in
degrees, minutes and seconds. The equator is given a value of 00. It is an
imaginary line which divides the Earth into two hemispheres. The Northern
hemisphere has a latitude of 90o N and
the Southern hemisphere has a latitude of 90o S.
Therefore,
Parallels of latitude are particular lines joining all points on the surface of
the earth and making an angle of 300o N with the equatorial plane.
How Latitudes and Longitudes are Determined
Describe
how latitudes and longitudes are determined
THE
IMPORTANT PARALLELS
The important parallels include:
1. Equator
0o
2. Tropic
of Cancer 23.5oN
3. Tropic
of Capricorn 23.5oS
4. Arctic
Circles 66.5oN
5. The
Atlantic Circle 66.5oS
LONGITUDE
Refers
to the angular distance measured in degrees East and West of the Greenwich
Meridian.
Prime
Meridian is the line running through the poles and the Greenwich observatory
near London. It is also known as Greenwich Meridian.
All
lines of longitude are semi circles of equal length. Lines of longitude are
also called meridians. There are 360o in a circle, 180o lie
east of the Greenwich Meridian and the other 180o west of Greenwich.
The
Greenwich lines have been chosen by convention (meaning that any other lines
could have served the same purpose).
CALCULATION
OF TIME
The
earth rotates on its own axis from West to East once every twenty four hours. This
means 360oof longitude are covered in a period of 24 hours or 1o in four minutes. There are places on a given meridian that
experience midday at the same time. Time recorded along the same meridian is
known as Local Mean Time (LMT).
Example 1
When the local time of Accra is 2.00pm what will be the local
time of Bangui 15 degrees E.
Solution
15
degrees - 0 degrees = 15 degrees
15 x 4
minutes = 60
60/60 =
1 hour
Accra
2.00 pm + 1.OO hour time difference = 3.00 pm
Importance of a Great Circle
Explain
the importance of a great circle
Any
circle which divides the globe into hemispheres is a great circle. The equator
is a great circle and Greenwich Meridian together with Meridian 1800 make
another great circle. The number of great circles is limit less.
The importance
of great circles in geological applications of spherical projections is that
they can represent planes. The center of a great circle is called its pole. If
you know a great circle, you can find its pole, and if you know the pole, you
can find the great circle. Thus it is possible to represent a plane by a single
point. This fact is extensively used in advanced projection techniques. The
perimeter of equatorial plane is called primitive circle.
CHARACTERISTICS
OF GREAT CIRCLES
1. All
great circles divide the earth (sphere) into two hemispheres.
2. A great
circle is the largest possible circle that can be drawn on the surface of the
sphere.
3. The
radius of great circles is the same as the radius of the earth.
USES OF GREAT CIRCLES
Great
circles are used to plot routes for ships crossing the vast oceans and aircraft
flying great distance in space. Ships and aircraft travel by following great
circles in order to save fuel and time because the shortest route between two
places is along the circle of the great circle which passes through them.
Importance of Parallels and Meridians
Discuss
the importance of parallels and meridians
Parallels
are another name for lines of latitude. You will see that these lines do not
converge, or come together, anywhere on the globe. We call these parallels
because they are always an equal distance apart. The first parallel is the
equator. It is latitude 0. Latitude measures distance north and south from the
Equator. Parallels are lines that circle the globe.
Meridians
are another name for lines of longitude. These lines are drawn on maps and
globes so that people can locate places. Meridians are lines that run from the
North Pole to the South Pole. Meridians are not parallel. They converge or come
together at the Poles. They number from the Prime Meridian (line 0) to 180W and
from the Prime Meridian to 180E.
Local time
Calculate
local time
Example 2
What is the local time at Morogoro-Tanzania when it is noon at
Kigali-Rwanda?
Procedure
1. Note
the longitudinal position between the two points Kigali 30°E and Morogoro 45°E
2. Find
the difference in degrees of longitude between Kigali and Morogoro 45 degrees -
30 degrees = 15 degrees
3. Multiply
the difference by 4 minutes 15°x 4 minutes = 60 minutes; 60 ÷ 60 = 1 hour
4. The
time difference is to be added (+) in case of places to the East of a point. In
case of place to the West, the time difference is subtracted (-). Since
Morogoro is to the East of Kigali, Morogoro time will be ahead of that of Kigali's
by 1 hour, therefore time for Morogoro will be:12.00 noon + 1 hour = 1.00 pm.
Time and Time Zone
Define
time and time zone
Time
means duration or suitable moment for some purpose.
Time
zone refers to a zone where standard time is accepted throughout a longitudinal
zone 150 in width.
Essence of Time and Time Zone
Explain
the essence of time and time zone
The
importance of time zones is to avoid the problems in telling time if every
place had its own time set according to the local mean time.
The
timetable of various human activities such as television and radio programs
would be confusing if they had to show different times.
As the
time varies from place to place, different stretches of land agreed to adopt
the time from certain meridian, that time is known as standard time.
East
African countries agreed to adopt standard time taken from meridian of 45oE.When
a whole stretch of land keeps to the same standard time that stretch of land
forms a time zone.
Variation of Standard Time in a Single Country
Explain
variation of standard time in a single country
Large
countries like USA, China, etc have several standard time zones with each time
zone covering about 15 degrees of longitude. There are 24 times zones in the
world. The starting point for dividing the world into 24 times zones is the
Greenwich Meridian. The standard time for Greenwich is known as the Greenwich
Meridian time (GMT).
International Date Line
Define
International Date Line
The
International Date Line is the line where date is changed or calendar day
begins. This line follows approximately the 1800 meridian.
Location of International Date Line
Locate
International Date Line
When
the time is 6.00pm on Monday 25th December, at Greenwich, the time at 1800 E
longitude will be 12 hours ahead of Greenwich Mean Time. The time at 1800 E
will be 6.00am on Tuesday 26th December. Therefore if one travels eastwards and
crosses the date line, one will gain a day whereas one who travels westwards
across the line will loose a day.
