WAEC SSCE - Geography - 2021 (Practical and Physical Geography)
Ajụjụ 1 Ripọtì
Explain how the following factors affect the temperature of a place:
(a) altitudes
(b) distance from the sea
(c) Slope and aspect
How the following factors affect the temperature of a place
(a) Altitude: temperature falls with increasing height above sea level, at an average rate of about 6.5 °C per 1000 m (the normal lapse rate). The air near the ground is warmed from below by the earth's surface, and it is also denser and holds more heat, dust and moisture. Higher up the air is thinner, drier and further from the heated surface, so it loses heat quickly. This is why highland areas such as Jos and mountain tops are cooler than surrounding lowlands on the same latitude.
(b) Distance from the sea (continentality): the sea heats and cools more slowly than the land. Coastal places have a small (moderate) temperature range because the sea warms them in winter and cools them in summer. Places far inland have a large temperature range, with very hot days/summers and cold nights/winters, because land heats and cools rapidly. Sea and land breezes also moderate coastal temperatures.
(c) Slope and aspect: the direction a slope faces (aspect) and its angle control how much insolation it receives. In the northern hemisphere, south-facing slopes face the sun and are warmer, while north-facing slopes are cooler and shaded (the reverse in the southern hemisphere). Slopes at right angles to the sun's rays receive concentrated heat over a small area and become warmer, while gentle or shaded slopes receive slanting rays spread over a wider area and stay cooler.
Akọwa Nkọwa
How the following factors affect the temperature of a place
(a) Altitude: temperature falls with increasing height above sea level, at an average rate of about 6.5 °C per 1000 m (the normal lapse rate). The air near the ground is warmed from below by the earth's surface, and it is also denser and holds more heat, dust and moisture. Higher up the air is thinner, drier and further from the heated surface, so it loses heat quickly. This is why highland areas such as Jos and mountain tops are cooler than surrounding lowlands on the same latitude.
(b) Distance from the sea (continentality): the sea heats and cools more slowly than the land. Coastal places have a small (moderate) temperature range because the sea warms them in winter and cools them in summer. Places far inland have a large temperature range, with very hot days/summers and cold nights/winters, because land heats and cools rapidly. Sea and land breezes also moderate coastal temperatures.
(c) Slope and aspect: the direction a slope faces (aspect) and its angle control how much insolation it receives. In the northern hemisphere, south-facing slopes face the sun and are warmer, while north-facing slopes are cooler and shaded (the reverse in the southern hemisphere). Slopes at right angles to the sun's rays receive concentrated heat over a small area and become warmer, while gentle or shaded slopes receive slanting rays spread over a wider area and stay cooler.
Ajụjụ 2 Ripọtì
(a) What is a Great Circle?
(b) Outline three characteristics of a Great Circle.
(c) If the time at longitude 100°E was 5 a.m on Monday, 11th April 2011, what was the
(i) time at longitude 10°W
(ii) day at longitude 10°W
(iii) date at longitude 10°W.
(a) What is a Great Circle?
A Great Circle is any circle drawn on the surface of the earth whose plane passes through the centre of the earth, thereby dividing the globe into two equal halves (hemispheres). It has the same circumference as the earth. Examples are the Equator and every pair of opposite meridians of longitude.
(b) Three characteristics of a Great Circle
- Its plane passes through the centre of the earth and divides the earth into two equal halves.
- It has the largest circumference possible on the globe, equal to that of the earth.
- The arc of a Great Circle gives the shortest distance between any two points on the earth's surface (used in air and sea navigation).
(c) Time calculation
Given time at 100°E = 5 a.m. on Monday, 11th April 2011. Find values at 10°W.
Difference in longitude \( = 100^\circ + 10^\circ = 110^\circ \).
Since \( 1^\circ = 4 \) minutes of time:
\[ 110 \times 4 = 440 \text{ minutes} = 7 \text{ hours } 20 \text{ minutes} \]
Because 10°W lies west of 100°E, its time is behind, so we subtract:
\[ 5{:}00 \text{ a.m. Monday} - 7\text{h }20\text{m} = 9{:}40 \text{ p.m.} \]
(i) Time at 10°W: 9:40 p.m. (21:40 hours).
(ii) Day at 10°W: Sunday.
(iii) Date at 10°W: 10th April 2011.
Akọwa Nkọwa
(a) What is a Great Circle?
A Great Circle is any circle drawn on the surface of the earth whose plane passes through the centre of the earth, thereby dividing the globe into two equal halves (hemispheres). It has the same circumference as the earth. Examples are the Equator and every pair of opposite meridians of longitude.
(b) Three characteristics of a Great Circle
- Its plane passes through the centre of the earth and divides the earth into two equal halves.
- It has the largest circumference possible on the globe, equal to that of the earth.
- The arc of a Great Circle gives the shortest distance between any two points on the earth's surface (used in air and sea navigation).
(c) Time calculation
Given time at 100°E = 5 a.m. on Monday, 11th April 2011. Find values at 10°W.
Difference in longitude \( = 100^\circ + 10^\circ = 110^\circ \).
Since \( 1^\circ = 4 \) minutes of time:
\[ 110 \times 4 = 440 \text{ minutes} = 7 \text{ hours } 20 \text{ minutes} \]
Because 10°W lies west of 100°E, its time is behind, so we subtract:
\[ 5{:}00 \text{ a.m. Monday} - 7\text{h }20\text{m} = 9{:}40 \text{ p.m.} \]
(i) Time at 10°W: 9:40 p.m. (21:40 hours).
(ii) Day at 10°W: Sunday.
(iii) Date at 10°W: 10th April 2011.
Ajụjụ 3 Ripọtì
(a) List three landforms associated with coastal erosion.
(b) Explain the following processes of wave erosion:
(i) hydraulic action:
(ii) COrrasion
(a) Three landforms associated with coastal erosion
- Cliffs (and the wave-cut platform at their base).
- Caves, arches and stacks (and stumps).
- Headlands and bays (also blow holes and geos).
(b) Processes of wave erosion
(i) Hydraulic action: this is the erosion caused by the sheer force of moving water. As waves break against a cliff, water is forced into cracks and joints in the rock. The air trapped in these cracks is suddenly compressed and then released as the wave retreats. This repeated compression and expansion weakens and shatters the rock, breaking pieces away. No rock fragments are needed; it is the power of the water and trapped air alone.
(ii) Corrasion (abrasion): this is the wearing away of the coast by the load carried by the waves. Waves pick up sand, pebbles and boulders and hurl them against the cliff face and drag them over the shore platform. This grinding and scraping action, like sandpaper, chips and smooths the rock, deepening notches and enlarging caves.
Akọwa Nkọwa
(a) Three landforms associated with coastal erosion
- Cliffs (and the wave-cut platform at their base).
- Caves, arches and stacks (and stumps).
- Headlands and bays (also blow holes and geos).
(b) Processes of wave erosion
(i) Hydraulic action: this is the erosion caused by the sheer force of moving water. As waves break against a cliff, water is forced into cracks and joints in the rock. The air trapped in these cracks is suddenly compressed and then released as the wave retreats. This repeated compression and expansion weakens and shatters the rock, breaking pieces away. No rock fragments are needed; it is the power of the water and trapped air alone.
(ii) Corrasion (abrasion): this is the wearing away of the coast by the load carried by the waves. Waves pick up sand, pebbles and boulders and hurl them against the cliff face and drag them over the shore platform. This grinding and scraping action, like sandpaper, chips and smooths the rock, deepening notches and enlarging caves.
Ajụjụ 4 Ripọtì
(a) Define environmental balance.
(b) With the aid of a diagram, explain the water cycle.
(c) In what three ways is the water cycle beneficial to man?
(a) Environmental balance
Environmental balance is the stable and sustainable state in an ecosystem in which living organisms and non-living components interact through the recycling of matter and the flow of energy without upsetting the system.
(b) Water cycle
The water cycle, or hydrological cycle, is the continuous circulation of water between water bodies, the atmosphere, the land and living things.
Explanation of the diagram
- Heat from the sun causes water in oceans, rivers, lakes and moist land to evaporate into the atmosphere as water vapour.
- Plants also release water vapour through transpiration.
- As the moist air rises and cools, the vapour condenses
- When the droplets become large and heavy, they fall as precipitation, mainly rainfall.
- Some rainwater flows over the land as surface runoff into rivers and back to the sea. Some infiltrates the soil as groundwater and also returns to rivers and the sea. The process then continues.
(c) Three benefits of the water cycle to man
- It supplies fresh water through rainfall, rivers, springs, wells and boreholes for drinking, washing and other domestic uses.
- It provides rainfall and soil moisture needed for agriculture and the growth of crops.
- It replenishes rivers, lakes and reservoirs used for industrial purposes and the generation of hydroelectric power.
Akọwa Nkọwa
(a) Environmental balance
Environmental balance is the stable and sustainable state in an ecosystem in which living organisms and non-living components interact through the recycling of matter and the flow of energy without upsetting the system.
(b) Water cycle
The water cycle, or hydrological cycle, is the continuous circulation of water between water bodies, the atmosphere, the land and living things.
Explanation of the diagram
- Heat from the sun causes water in oceans, rivers, lakes and moist land to evaporate into the atmosphere as water vapour.
- Plants also release water vapour through transpiration.
- As the moist air rises and cools, the vapour condenses
- When the droplets become large and heavy, they fall as precipitation, mainly rainfall.
- Some rainwater flows over the land as surface runoff into rivers and back to the sea. Some infiltrates the soil as groundwater and also returns to rivers and the sea. The process then continues.
(c) Three benefits of the water cycle to man
- It supplies fresh water through rainfall, rivers, springs, wells and boreholes for drinking, washing and other domestic uses.
- It provides rainfall and soil moisture needed for agriculture and the growth of crops.
- It replenishes rivers, lakes and reservoirs used for industrial purposes and the generation of hydroelectric power.
