Meaning of Geography

The Meaning of the Term Geography

Definition of 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. This led to the early definition of geography as the description of the Earth by words, maps, and statistics, including both the physical Earth and everything found on it, such as plants, animals, and people.

Modern Definition:
Geography is the study of the distribution and interrelationship of phenomena in relation to the Earth’s surface. Alternatively, it can be described as the study of the Earth and its environment.

Branches of Geography

There are two main branches of Geography:

1. Physical Geography: Focuses on land formation processes, weather, and climate.
2. Human and Economic Geography: Involves the study of human activities on the Earth’s surface.

Interrelationship Between Different Geographical Phenomena

Geographical phenomena refer to facts or circumstances observed within nature. These phenomena can be physical or human-related.

Examples of Interrelationships:

• Land and Plants: Land resources provide soil that supports plant growth.
• Sun and Water Cycle: Sun rays generate heat, causing water to evaporate, form clouds, and eventually rain.
• Climate and Living Organisms: Climate determines the types of plants and animals that can survive in a particular area and influences human population distribution.
• Human Impact on Environment: Human activities can modify physical environments, such as soil degradation, land reclamation, and forest conservation.

Components of the Solar System

Naming the Components of the Solar System

The solar system consists of:

• The Sun
• Planets
• Comets
• Asteroids
• Meteors
• Satellites

Importance of the Components of the Solar System

• Sun: Produces heat and light necessary for living organisms.
• Earth: Provides a habitat for humans and other living organisms.
• Meteors: Form craters that become attractive sites for tourism.

The Sun

Dimension of the Sun in Relation to Other Space Bodies

• Size: The diameter of the Sun is 1.4 million kilometers.

Characteristics of the Sun

• Composition: Approximately 75% Hydrogen, 23% Helium, and 3% other elements (e.g., Carbon, Iron, Oxygen, Silicon).
• Temperature: Estimated to be 20,000,000 degrees Centigrade.

Solar Energy

Definition of Solar Energy

Solar energy is the heat and light produced by the Sun. It is the source of all energy on Earth.

Uses of Solar Energy

• Drying clothes, meat, fish, fruits, and grains
• Photosynthesis in plants
• Generation of electricity
• Formation of coal, gas, and oil
• Formation of clouds and rainfall
• Powering small radios and telephone systems using solar batteries
• Providing Vitamin D to human bodies
• Domestic purposes like cooking and heating water

Environmental Conservation Through Solar Energy

Using solar energy reduces the need for industrially produced chlorofluorocarbon gases, which deplete the ozone layer and cause global warming. It also reduces the depletion of forests for charcoal and firewood.

Emancipation of Women Through Solar Energy

Reduced Time Burdens: Access to energy allows for more efficient products, reducing domestic responsibilities and creating time for higher-earning jobs and entrepreneurial opportunities.

Improved Living Conditions: Access to electricity improves women’s health, nutrition, safety, and education, facilitating their participation in the local economy.

The Planets

Locating the Planets in the Solar System

The solar system has eight planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Pluto is no longer considered a planet due to its small size and irregular orbit.

Relative Distance of Planets from the Earth

Planets are measured in Astronomical Units (AU), with 1 AU being the average distance from Earth to the Sun (about 150 million kilometers or 93 million miles).

Characteristics of Comets, Asteroids, Meteors, and Satellites

• Comets: Objects with leading heads and bright tails, composed of ice crystals and solid matter fragments, with highly elongated orbits around the Sun.
• Asteroids: Solid bodies revolving around the Sun, mostly found between Mars and Jupiter, viewable only with a telescope.
• Meteors: Pieces of hard matter from outer space that become hot and disintegrate due to atmospheric friction, falling as meteorites.
• Satellites: Small bodies that rotate on their axis and revolve around planets; seven planets have satellites, with 57 known in the solar system.

Local Incidents Linked to Meteorites

In Tanzania, meteorites are found in Mbozi district (Mbeya region) and Malampaka (Kwimba district, Mwanza region), resulting in crater formation.

The Earth

The Shape of the Earth and Its Evidence

Evidence of Earth’s Spherical Shape

1. Circumnavigation: Ferdinand Magellan’s voyage around the world proved Earth’s sphericity.
2. Circular Horizon: Viewed from sea or land, the horizon is always circular, widening with altitude.
3. Ship’s Visibility: Ships appear and disappear gradually over the horizon, not all at once.
4. Sunrise and Sunset: Different times in different places indicate a spherical Earth.
5. Lunar Eclipse: Earth’s shadow on the Moon is always circular.
6. Planetary Bodies: Observations show other celestial bodies are spherical.
7. Driving Poles: Engineers observe the curvature of Earth when driving poles at regular intervals.
8. Space Photographs: Images from satellites show Earth’s curved edge.

Earth’s Movements

Types of Earth’s Movements

1. Rotation: Spinning of Earth on its axis, causing day and night.
2. Revolution: Earth’s orbit around the Sun, causing seasons.

Rotation

Definition: The spinning of Earth on its axis from West to East.
Evidence: Star movement, travel observations, sunrise and sunset, day and night.
Significances: Alternation of day and night, ocean tides, wind and ocean current deflection, time difference between longitudes.

Revolution

Definition: Earth’s elliptical orbit around the Sun.
Process: Earth is at aphelion on July 4 (farthest from Sun) and perihelion on January 3 (closest to Sun).
Result: Causes seasons, changes in the position of the midday sun, and varying lengths of day and night.

The Importance of Parallels and Meridians

Defining Parallels and Meridians

Latitude refers to the angular distance North or South of the equator, measured in degrees, minutes, and seconds. The equator, an imaginary line dividing the Earth into two hemispheres, is assigned a value of 0°. The Northern Hemisphere extends to 90°N, while the Southern Hemisphere extends to 90°S. Parallels of latitude are lines joining all points on the surface of the Earth, making an angle of 30°N with the equatorial plane.

Longitude refers to the angular distance measured in degrees East and West of the Greenwich Meridian, also known as the Prime Meridian. This line runs through the poles and the Greenwich Observatory near London. All lines of longitude are semicircles of equal length, called meridians, and there are 360° in a circle: 180° lie east of the Greenwich Meridian and 180° lie west. The Greenwich line was chosen by convention, meaning any other line could serve the same purpose.

Important Parallels

The important parallels include:

• Equator: 0°
• Tropic of Cancer: 23.5°N
• Tropic of Capricorn: 23.5°S
• Arctic Circle: 66.5°N
• Antarctic Circle: 66.5°S

Calculation of Time

The Earth rotates on its axis from West to East, completing one rotation every twenty-four hours. This means 360° of longitude are covered in 24 hours, or 1° in four minutes. Local Mean Time (LMT) is the time recorded along the same meridian.

Example 1

When the local time in Accra is 2:00 PM, what will be the local time in Bangui, 15°E?

1. Difference in degrees: 15° – 0° = 15°
2. Time difference: 15° × 4 minutes = 60 minutes = 1 hour
3. Local time in Bangui: 2:00 PM + 1 hour = 3:00 PM

Importance of a Great Circle

A great circle is any circle that divides the globe into hemispheres. The equator is a great circle, and the Greenwich Meridian, along with Meridian 180°, makes another great circle. Great circles have several important characteristics and uses.

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 vast oceans and for aircraft flying great distances. Ships and aircraft follow great circles to save fuel and time because the shortest route between two places is along the circle of the great circle passing through them.

Importance of Parallels and Meridians

Parallels are another name for lines of latitude. These lines are always an equal distance apart and circle the globe. The equator is the first parallel at latitude 0°, measuring distance north and south from the Equator.

Meridians are lines of longitude running from the North Pole to the South Pole. These lines are drawn on maps and globes to locate places. Unlike parallels, meridians converge at the Poles and number from the Prime Meridian (line 0) to 180°W and from the Prime Meridian to 180°E.

Local Time Calculation

Example 2

What is the local time in Morogoro, Tanzania, when it is noon in Kigali, Rwanda?

1. Longitudinal positions: Kigali 30°E, Morogoro 45°E
2. Difference in degrees: 45° – 30° = 15°
3. Time difference: 15° × 4 minutes = 60 minutes = 1 hour
4. Morogoro time: 12:00 noon + 1 hour = 1:00 PM

Time and Time Zones

Time refers to duration or a suitable moment for some purpose. A time zone is a zone where standard time is accepted throughout a longitudinal zone 15° in width.

Importance of Time and Time Zones

Time zones prevent confusion that would arise if every place had its own time set according to the local mean time. Timetables for various activities, like television and radio programs, would be confusing without standard time zones. For example, East African countries have adopted standard time from the meridian of 45°E.

Variation of Standard Time in a Single Country

Large countries like the USA and China have several standard time zones, each covering about 15 degrees of longitude. There are 24 time zones worldwide, starting from the Greenwich Meridian. The standard time for Greenwich is known as Greenwich Mean Time (GMT).

International Date Line

The International Date Line is where the date changes or the calendar day begins. This line follows approximately the 180° meridian.

Location of International Date Line

When it is 6:00 PM on Monday, 25th December, at Greenwich, the time at 180°E longitude will be 12 hours ahead of GMT, making it 6:00 AM on Tuesday, 26th December. Traveling eastwards across the date line gains a day, while traveling westwards loses a day.