WAEC SSCE - Geography - 2020 (Practical and Physical Geography)
Question 1 Report
(a) Define climate.
(b) Draw the globe and show the three climatic belts of the Greek System of Classification.
(c) List three areas of hot deserts
(d) Outline three characteristics of hot deserts.
(a) Definition of climate
Climate is the average condition of the atmosphere of a place, determined from observations of weather elements over a long period, usually about 30 to 40 years.
(b) Climatic belts of the Greek system of classification
The Greeks classified the world into three main climatic belts: the Frigid, Temperate and Torrid belts. The Frigid and Temperate belts each occur in both hemispheres.
(c) Three areas of hot deserts
- The Sahara Desert of North Africa.
- The Arabian Desert of the Middle East.
- The Thar Desert of India and Pakistan.
(d) Characteristics of hot deserts
- Rainfall is very low, usually below 250 mm annually, and is unreliable, infrequent and often torrential when it occurs.
- Temperatures are high, commonly above 30°C during the day, with a large daily range of temperature and cold nights.
- Evaporation is high because skies are mostly cloudless, humidity is low and insolation is intense.
- Vegetation is sparse and consists mainly of drought-resistant, xerophytic plants.
- Wind action is important, producing dust storms, sand dunes and other wind-eroded features.
Answer Details
(a) Definition of climate
Climate is the average condition of the atmosphere of a place, determined from observations of weather elements over a long period, usually about 30 to 40 years.
(b) Climatic belts of the Greek system of classification
The Greeks classified the world into three main climatic belts: the Frigid, Temperate and Torrid belts. The Frigid and Temperate belts each occur in both hemispheres.
(c) Three areas of hot deserts
- The Sahara Desert of North Africa.
- The Arabian Desert of the Middle East.
- The Thar Desert of India and Pakistan.
(d) Characteristics of hot deserts
- Rainfall is very low, usually below 250 mm annually, and is unreliable, infrequent and often torrential when it occurs.
- Temperatures are high, commonly above 30°C during the day, with a large daily range of temperature and cold nights.
- Evaporation is high because skies are mostly cloudless, humidity is low and insolation is intense.
- Vegetation is sparse and consists mainly of drought-resistant, xerophytic plants.
- Wind action is important, producing dust storms, sand dunes and other wind-eroded features.
Question 2 Report
(a) List five factors that affect climate.
(b) Highlight five characteristics of Equatorial climate.
(a) Five factors that affect climate
- Latitude (distance from the equator): places near the equator receive more direct, intense insolation and are hotter than places near the poles.
- Altitude (height above sea level): temperature falls with height (about \(6.5^{\circ}\text{C}\) per \(1000\text{ m}\)), so highlands are cooler than lowlands.
- Distance from the sea (continentality): coastal areas have a small temperature range while interiors have hot summers and cold winters.
- Ocean currents: warm currents raise the temperature and rainfall of adjacent coasts, while cold currents lower them.
- Prevailing winds and relief (aspect): onshore moist winds bring rain, offshore dry winds do not, and windward slopes are wetter than leeward slopes.
(Vegetation cover and cloud cover are also acceptable.)
(b) Five characteristics of the Equatorial climate
- High temperatures all year: mean monthly temperature is about \(27^{\circ}\text{C}\), with a very small annual range (about \(2^{\circ}\text{C}\)).
- Heavy rainfall throughout the year: totals exceed \(2000\text{ mm}\), with no true dry season (double maxima near the equinoxes).
- High relative humidity: often above 80 per cent, giving a hot, damp, uncomfortable feel.
- Convectional rainfall: intense afternoon thunderstorms occur almost daily due to strong heating and rising moist air.
- Small diurnal and seasonal contrast with heavy cloud cover: days are consistently hot, humid and cloudy with little seasonal variation.
Answer Details
(a) Five factors that affect climate
- Latitude (distance from the equator): places near the equator receive more direct, intense insolation and are hotter than places near the poles.
- Altitude (height above sea level): temperature falls with height (about \(6.5^{\circ}\text{C}\) per \(1000\text{ m}\)), so highlands are cooler than lowlands.
- Distance from the sea (continentality): coastal areas have a small temperature range while interiors have hot summers and cold winters.
- Ocean currents: warm currents raise the temperature and rainfall of adjacent coasts, while cold currents lower them.
- Prevailing winds and relief (aspect): onshore moist winds bring rain, offshore dry winds do not, and windward slopes are wetter than leeward slopes.
(Vegetation cover and cloud cover are also acceptable.)
(b) Five characteristics of the Equatorial climate
- High temperatures all year: mean monthly temperature is about \(27^{\circ}\text{C}\), with a very small annual range (about \(2^{\circ}\text{C}\)).
- Heavy rainfall throughout the year: totals exceed \(2000\text{ mm}\), with no true dry season (double maxima near the equinoxes).
- High relative humidity: often above 80 per cent, giving a hot, damp, uncomfortable feel.
- Convectional rainfall: intense afternoon thunderstorms occur almost daily due to strong heating and rising moist air.
- Small diurnal and seasonal contrast with heavy cloud cover: days are consistently hot, humid and cloudy with little seasonal variation.
Question 3 Report
(a)Lst five landforms found in the upper course of a river.
(b) Highlight three differences and two Similarities between an alluvial fan and a delta.
(a) Five landforms found in the upper course of a river
- V-shaped valley (deep, narrow valley cut by vertical erosion).
- Interlocking spurs (projecting ridges the river winds around).
- Waterfalls (and rapids where the river crosses hard rock bands).
- Gorges (steep-sided rocky valleys, often below a retreating waterfall).
- Potholes (circular hollows drilled into the rocky bed by swirling pebbles).
(Cascades and cataracts are also acceptable.)
(b) Alluvial fan and delta compared
Three differences
| Alluvial fan | Delta |
|---|---|
| Forms on land, where a river leaves a steep highland and reaches a plain. | Forms at the mouth of a river, where it enters a sea or lake. |
| Deposition is caused by a sudden reduction in gradient/slope. | Deposition is caused by the check of the current on meeting standing water and flocculation. |
| Built of coarser materials (gravel, sand) and is usually cone-shaped in profile. | Built of finer materials (silt, mud, clay) and is often triangular or bird-foot in plan. |
Two similarities
- Both are depositional landforms built from river load (alluvium).
- Both are formed where the river's velocity and carrying capacity fall sharply, and both have gentle, fan-like or spreading shapes crossed by distributaries.
Answer Details
(a) Five landforms found in the upper course of a river
- V-shaped valley (deep, narrow valley cut by vertical erosion).
- Interlocking spurs (projecting ridges the river winds around).
- Waterfalls (and rapids where the river crosses hard rock bands).
- Gorges (steep-sided rocky valleys, often below a retreating waterfall).
- Potholes (circular hollows drilled into the rocky bed by swirling pebbles).
(Cascades and cataracts are also acceptable.)
(b) Alluvial fan and delta compared
Three differences
| Alluvial fan | Delta |
|---|---|
| Forms on land, where a river leaves a steep highland and reaches a plain. | Forms at the mouth of a river, where it enters a sea or lake. |
| Deposition is caused by a sudden reduction in gradient/slope. | Deposition is caused by the check of the current on meeting standing water and flocculation. |
| Built of coarser materials (gravel, sand) and is usually cone-shaped in profile. | Built of finer materials (silt, mud, clay) and is often triangular or bird-foot in plan. |
Two similarities
- Both are depositional landforms built from river load (alluvium).
- Both are formed where the river's velocity and carrying capacity fall sharply, and both have gentle, fan-like or spreading shapes crossed by distributaries.
Question 4 Report
(a) Define atmospheric condition.
(b) List four major sources of air pollutants.
(c) Highlight four effects of atmospheric pollution.
(a) Definition of atmospheric condition
Atmospheric condition refers to the physical state of the atmosphere of a place at a given time, described by the weather elements such as temperature, rainfall, humidity, wind, pressure, cloud cover and the degree of purity or pollution of the air.
(b) Four major sources of air pollutants
- Industrial activities/factories: smoke, soot and gases (\(\text{SO}_2\), \(\text{CO}_2\)) from manufacturing and processing plants.
- Motor vehicles and other transport: exhaust fumes containing carbon monoxide, lead and hydrocarbons.
- Bush burning and burning of fossil fuels: release of smoke, ash and carbon gases.
- Gas flaring and oil operations: flares from oil fields (as in the Niger Delta) emit large volumes of gases and soot.
(Others: refuse/waste incineration, power stations, volcanic eruptions and dust.)
(c) Four effects of atmospheric pollution
- Respiratory and other diseases: polluted air causes bronchitis, asthma, lung cancer and eye irritation.
- Acid rain: sulphur and nitrogen oxides dissolve in rain, damaging crops, forests, buildings and water bodies.
- Global warming and climate change: greenhouse gases such as carbon dioxide trap heat, raising temperatures and disrupting rainfall.
- Depletion of the ozone layer: gases such as CFCs thin the ozone shield, increasing harmful ultraviolet radiation.
(Also: reduced visibility/smog, poor plant growth and lower agricultural yields.)
Answer Details
(a) Definition of atmospheric condition
Atmospheric condition refers to the physical state of the atmosphere of a place at a given time, described by the weather elements such as temperature, rainfall, humidity, wind, pressure, cloud cover and the degree of purity or pollution of the air.
(b) Four major sources of air pollutants
- Industrial activities/factories: smoke, soot and gases (\(\text{SO}_2\), \(\text{CO}_2\)) from manufacturing and processing plants.
- Motor vehicles and other transport: exhaust fumes containing carbon monoxide, lead and hydrocarbons.
- Bush burning and burning of fossil fuels: release of smoke, ash and carbon gases.
- Gas flaring and oil operations: flares from oil fields (as in the Niger Delta) emit large volumes of gases and soot.
(Others: refuse/waste incineration, power stations, volcanic eruptions and dust.)
(c) Four effects of atmospheric pollution
- Respiratory and other diseases: polluted air causes bronchitis, asthma, lung cancer and eye irritation.
- Acid rain: sulphur and nitrogen oxides dissolve in rain, damaging crops, forests, buildings and water bodies.
- Global warming and climate change: greenhouse gases such as carbon dioxide trap heat, raising temperatures and disrupting rainfall.
- Depletion of the ozone layer: gases such as CFCs thin the ozone shield, increasing harmful ultraviolet radiation.
(Also: reduced visibility/smog, poor plant growth and lower agricultural yields.)
