SECTION A:
ANSWER ALL THE QUESTIONS:
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- State three forces that influence the shape of the earth. (3 mks)
- State three proofs that show that the earth is spherical. (3 mks)
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- Distinguish between a rock and a mineral. (2 mks)
- Give the metamorphic equivalent of the following rocks. (3 mks)
Original rock metamorphic- Granite –
- Limestone –
- Shale –
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- What is the longitude of a place M whose local time is 11.00 am. If the local time at longitude 30°E is 2.00 pm. (3 mks)
- State the effect of the International Date Line. (1 mk)
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- What is Mass Wasting. (2 mks)
- State 3 factors which affects the rate of mass wasting. (3 mks)
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- Define the term Vulcanicity. (2 mks)
- Name
- Two Intrusive landforms (2 mks)
- Two Extrusive landforms (2 mks)
SECTION B:
ANSWER QUESTIONS SIX (COMPULSORY) AND ANY OTHER TWO QUESTIONS.
- Study the map of Karatina (1:50,000) sheet 121/3 provided and answer the following questions.
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- What type of map is Karatina? (1 mk)
- Convert the scale used in the map into a statement scale. (2 mks)
- Outline 3 marginal information which you can be able to identify from the map given. (3 mks)
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- Citing evidence from the map, use list three social functions of the area covered by the map. (6 mks)
- Name 3 human made features from the map. (3 mks)
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- Citing evidence from the map explain three economic activities of the area covered by the map.
- Describe the drainage of the area covered by the map. (4 mks)
- Give two types of vegetation found in the area covered by the map. (2 mks)
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- Name three types of faults. (3 mks)
- Apart from compressional force explain two other processes that may cause faulting. (4 mks)
- With aid of diagrams, describe how compressional forces may have lead to the formation of the Great Rift Valley. (8 mks)
- Explain five ways in which faulting is of significance to human activities. (10 mks)
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- The table below shows Rainfall and Temperature figures of a station in North America.
Month J F M A M J J A S O N D Rainfall in mm 15 8 8 13 31 51 51 51 28 25 18 20 Temp (°C) −22 −19 −12 −1 4 10 11 11 5 −11 −18 −20 - On the graph paper provided, draw a bar graph to represent the rainfall figures. (Use a vertical scale of 1cm represent 10 mm) (5 mks)
- Give four characteristics of a bar graph you have drawn. (4 mks)
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- Calculate the mean of temperature for the station. Show your working. (2 mks)
- State five characteristics of the climate experienced in the station. (5 mks)
- You intend to carry out a field study on vegetation around the station with the above climate.
- State 3 methods you would use to collect the data. (3 mks)
- Highlight 3 methods you are likely to use to record the data. (2 mks)
- State 3 problems you are likely to face during the field study.
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- Name three types of physical weathering. (3 mks)
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- Give three factors that influence the rate of weathering. (3 mks)
- Describe two causes of biological weathering. (6 mks)
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- Give five types of chemical weathering. (5 mks)
- Explain four significances of weathering to human activities. (8 mks)
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- What is aridity? (2 mks)
- What is desertification. (2 mks)
- State five causes of aridity and desertification. (5 mks)
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- Explain 5 effects of aridity and desertification. (10 mks)
- Suggest 3 possible solutions to aridity and desertification. (6 mks)
Marking Scheme
SETION A
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- Forces that influence the shapes of the earth.
- Force of gravity
- Centripetal force
- Centrifugal force (3x1=3 mks)
- Proofs the show that the earth is spherical.
- Photographs taken from the outer space /satellites shows that the earth is spherical.
- During the lunar eclipse, the earth casts a spherical shaped shadow on the moon.
- All parents in the solar system are spherical therefore the earth being one of the planets on the solar system is also spherical.
- Circumnavigation of the earth along a straight path while maintaining one direction will bring back to the same starting point from the opposite direction.
- The earths horizon when viewed from a very high tower or in an aeroplane always appears curved. (3x1 =3mks)
- Forces that influence the shapes of the earth.
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- A rock – is an aggregate of mineral particles forming the solid part of the earth. While A mineral is an inorganic substance which occur naturally at or beneath the surface of the earth
- ROCK METAMORPHIC ROCK
- Granite Gneiss
- Limestone Marble
- Shale Schist/slate
(3x1=3 mks)
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- Difference in time from 2.00 pm to 11.00 am = 3 hrs.
In 1 hr, the earth rotates through 15°
Therefore in 3 hrs the earth will rotate through 3x15° = 45°
Time at M is behind that at 30°E
Get the difference between the angles
= 45° – 30°= 15°
M is at longitude 15°W. (3 mks) - Effects of the International date
- On crossing this longitude while going to the west a day is lost.
- If you cross it going to the East a day is gained. (1 mk)
- Difference in time from 2.00 pm to 11.00 am = 3 hrs.
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- Mass wasting.
- This is the creeping, flowing, sliding or falling of weathered rocks down the slope under the influence of gravitational force. (2 mks)
- Factors that influence the rate of mass wasting.
- Amount of water in the weathered material.
- Nature of the weathered material.
- Gradient of the slope.
- Presence of vegetation cover.
- Human activities eg. mining and construction.
- Tectonic movements may trigger earth quakes causing vibration of the earth’s surface hence some materials move down slope.
- Climatic conditions especially rainfall and temperature. (3x1=3 mks)
- Mass wasting.
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- Vulcanicity
- This refers to all the processes by which solids, liquids, molten and gaseous. Materials are forced into the earth’s crust or ejected onto its surface.
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- Intrusive land forms:
- Batholith
- Laccolith
- Dykes
- A sill
- Lopolith
- Pacolith (2x1=2mks)
- Extrusive landforms
- Volcanoes
- Basalt lava domes or shield domes
- Acid lava cones
- Composite volcanoes
- Ash and under cones
- Plug dome volcano
- Volcanic plug (2x1=2 mks)
- Intrusive land forms:
- Vulcanicity
SECTION B-MAPWORK
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- Topographical map. (1 mk)
- 1:50,000
1 cm rep. 0.5 km (2 mks) - Marginal information.
- Map series
- Grind system numbers
- Sheet number
- Latitudes /longitudes
- Sheet editor
- Compass direction
- Map name (any 4x1=4 mks)
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- Citing evidence from the map (social functions).
- Educational since there is a school ie. Gaikkuyu school
- Trading since there is market ie Giakagina mkt.
- Transportation since there is a road.
- Administrative since there is a chiefs office.
- Agriculture since there is coffee factory and tea centre.
- Religions centre evidence churches. (NB. No evidence no mark)
- human made features
- Road
- Shops
- Cattle dips
- Coffee factory
- Tea centres (any 3x1=3 mks)
- Citing evidence from the map (social functions).
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- Economic activities carried out in the area covered by the map.
- Transport – all weather road/dry weather road.
- Trade – shops/markets
- Crop farming – coffee factory (No evidence no mark) (3x1=3 mks)
- Drainage of the area covered by the map.
- Dam present
- There are permanent rivers.
- Rivers flow from North to South.
- There are many permanent rivers. (4x1=4 mks)
- Two types of vegetation found in the area covered by the map.
- Forest
- Papynes swamp (2x1=2 mks)
- Economic activities carried out in the area covered by the map.
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- Normal reverse.
- Tear, sheer or slip
- Thrust
- Anticlinal (3 mks)
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- Tensional forces - causes movement of landmasses away from one another.
They pull landmasses apart resulting into tearing. (2 mks) - Shear forces - causes the movement of land masses alongside one another along a crack.
- Line of weakness.-The mass of land move in opposite directions. (2 mks)
- Tensional forces - causes movement of landmasses away from one another.
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- Lines of weakness occur reverse faults.
- The outer blocks are pushed over the middle blocks leaving it to form the plain of Rift valley.
- The over logging sides caused to reverse fault collapse. (4mks – txt – 4 mks diagrams)
- Significant of faulting
- Disjointing of land to disruption of communication lines, water sewage etc.
- Sinking of land lead to loss of property and life ie. agricultural farm.
- Vertical faulting across a river may cause waterfall which may be used to generate H.E.P project.
- Hot springs and geysers like hot springs attract tourist who bring in foreign exchange.
- Hot spring and geysers associated to faulting can unharnessed for geothermal power. (10 mks)
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- Title (1 mk)
- Labeling (1 mk)
- Bans (3 mks)
Total (5 mks)
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- The bars are verified
- The bars starts from zero
- They are drawn side by side
- Have a title
- Have uniform width. (4x1=4 mks)
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- Mean of the temperature
Add then divide by 12
−22+−19+−12+−1+4+10+11+11+5+−11+−18+−20=
= −62 = −5.167 =−5
12 - Characteristics of climate in the station
- Minimal range of temp. is very large.
- The coldest month is January.
- Highest rainfall occurs when temperature is high.
- The total annual rainfall is low 319 mm.
- The months of March and February records the lowest rainfall.
- Hottest month is July and August.
- Region experience rainfall through the year.
- Mean of the temperature
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- Methods used to collect the data
- Observation
- Interviewing
- Administering questionnaires
- Content analysis
- Measuring
- Photographing
- Methods used to record the data
- note taking -filling in questionnaires
- tallying - drawing
- tabulation - tape recording (2x1=2 mks)
- Problems experienced during the study.
- Lack of cooperation from potential respondents.
- Poor weather conditions.
- Incorrect information from the respondents. (3x1=3 mks)
- Methods used to collect the data
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- Three types of physical weathering.
- Exfoliation
- Block disintegration
- Granular disintegration
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- Climate
- Topography
- Chemical composition of the rock
- Rock structure
- Rock texture
- Biological organisms (6x1 = 6 mks)
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- Action by plants
- Roots of plants penetrate grow into joints or cracks.
- As the trees grow bigger, the root also grow bigger widening the joints and cracks.
- Blocks separate in what is called wedging mechanism. (3 mks)
- Action of animals
- Burrowing animals such as moley rabbits, Earth worms break off small bits of rocks from the main rock.
- By digging these animals expose a large surface area to other weathered processes.
- Large herds of cattle and Zebras’ bound the rock with there hooves as they move breaking them into smaller particles. (any 3x1=3 mks)
- Action by plants
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- Five types of chemical weathering
- Solution
- Carbonation
- Hydrolysis
- Hydration
- Oxidation (5x1=5 mks)
- Significance of weathering to human activities
- Weathering weakens rocks making them easier for man to quarry or mine .
- Some rocks form through weathering eg. Granite tors are conspicuous thus attacking tourists .
- Weathering produces clay which is used in making bricks. Bricks are used for building houses.
- Weathering leads to the formation of fertile soils which enhances agriculture .(Any 4x2=8 mks)
- Five types of chemical weathering
- Three types of physical weathering.
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- What is aridity. (2 mks)
- It is a state of contiunous deficiency of moisture in the ground leading to scant/little vegetation.
- What is desertification. (2 mks)
- It is a process of slow but steady encronchment of desert like conditions to large areas leading to barrenness.
- State the causes of aridity and desertification.
- Insufficient rainfall
- High temperatures
- Location of leeward sides of the mountains
- Presence of cold ocean currents on adjacent coasts.
- Location of places very far away from the coast.
- Presence of stable high pressure systems with low humidity.
- Man’s destruction of vegetation. (any 5x1=5 mks)
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- Explain the effects of aridity and desertification.
- Desertification leads to loss of soil fertility leading to a decrease in crop production.
- Reduced food production can lead to famine in the affected areas.
- Desertification leads to destruction of water catchment areas/insufficient supplies of water for domestic use.
- Drying up of vegetation due to desertification leads to exposure of land to agents of erosion.
- Desertification may trigger migration from the affected areas due to drought and decreasing food production.
- Aridity and desertification can lead to extinction of some plants and animal species. (any 5x2=10 mks)
- Suggest possible solutions to aridity and desertification.
- Enacting law that curbs production.
- Embarking of reafforestation and afforestation programmes.
- Taking soil erosion control measures ie. building gabions.
- Introducing modern farming methods which can renew soil fertility.
(any 3x2=6 mks)
- Explain the effects of aridity and desertification.
- What is aridity. (2 mks)
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