LAINAKU FORM 3 GEOGRAPHY PAPER 1 2014
MARKING SCHEME
SECTION A
1. a) What is a longitude?

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(2mks)
It is an imaginary line which is drawn on a map from north pole to south pole and is
measured in degrees east or west of prime meridian (00)
It is a line based on angular distance of a place east or west of the prime meridian.
a) What is the local time at Harare 300E when the local time at Kismayu 400E is 12.00
noon?
(2mks)
400-300 = 100
10 x 4 = 40 minutes
Kismayu = 12.00 – 40 mins = 11.20 AM
2. a) The diagram below shows a simple hygrometer. Identify the parts marked A, B and
C.
(3mks)
A- muslin,
B-dry bulb,
C--mercury
b) Give three factors that influence relative humidity.
 Distance from large water bodies/seas
 Altitude
 Natural vegetation/forests
 Latitude
 Temperature
3. a) Give three characteristics of sedimentary rocks.
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(3mks)
(3mks)
Some contain fossils
They have bedding planes/cleavage/are foliated
They form horizontal layers/stratified
They are non-crystalline
b) Define the term rock

Naturally formed mineral aggregate/Naturally occurring solid material composed of
one or more minerals.
4. a) Give two categories of vegetation
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Natural
Semi-natural/secondary/Derived
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Planted/cultivated
b) Study the world map below showing vegetation zones and answer the questions that
follow. Identify vegetation zones marked D, E and F.
 D - Tropical forests/Rain forests
 E – Tropical Deserts
 F – Tundra vegetation
5. Draw a well labeled diagram of a hydrological cycle
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Water body/land/sea/ocean
Evaporation/Evapotranspiration
Condensation level
Clouds
Rain
Surface runoff
Infiltration/Percolation
(5mks)
(1mk)
(1mk)
(1mk)
(1mk)
(1mk)
(1mk)
(1mk)
SECTION B
Answer question 6 and any other two question form this section
6. a) Give two districts represented in the area covered by the map.
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Nyeri District
Kirinyaga District
ii) Convert the ration scale used in the map to statement scale.

(2mks)
1:50 000 = 1cm rep 50 000 cm
1cm rep 0.5km (1/2km)
iii) Identify two natural features found in grid square 8463
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(2mks)
(2mks)
a hill
a river
forest/trees
iv What is the latitudinal extent of the area covered by the map.
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0015’s to 0030’s / 15◦
b. i) Measure the distance of a section of the railway line form level crossing in grid square
8652 to the western edge of the map. Give your answer in km.
(2mks)

9.1 +/_ (9 – 9.2 km)
ii) Calculate the bearing of a water reservoir in grid square 9054 from a cattle dip in grid
square 9952.
(2mks)
281◦ ± 1º (280-------282º)
c) i) Draw a square measuring 12cm by 12cm to represent the area enclosed by Easting 81
and 93 and Northings 45 and 57.
(1mk)
(1mk)
d) Explain two factors which have influenced the distribution of settlements in the area
covered by the map.
(4mks)
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
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There are few settlement in the forest because it is a protected area
There are few/none settlement at along river valleys for fear of flooding.
Around the papyrus swamp to the southeast there are no settlements because the area
is unstable for construction of houses/marshy
 There is dense settlement in Karatina Township because of availability of services
ii) Giving evidence from the map identify four economic activities carried out in the area
covered by the map.
Activity
Evidence
 Trading
Markets/shops
 Foresty
Forest station/forest staff quarters
 Transportation
Roads/railway
 Fishing
Fisheries research
 Crop farming
Tea centre/coffee factory
 Animal rearing
Cattle dips
 Processing
Coffee/Tea factories
7. a) i) Differentiate between weathering and mass-wasting.
(2mks)
 Weathering is the breakdown and decomposition of rocks at or near the earth surface
insity while mass-wasting is the movement of weathered materials downslope under
influence of gravity.
ii) Give three processes of physical weathering caused by temperature change.
 Exfoliation, Block disintegration, Granular disintegration.
iii) Explain two ways in which plants causes weathering.
 Plant root penetrates cracks in the rocks, widening them and eventually rock break
up.
 Plant absorbs minerals from rocks hence weakening them.
 Rotting plants releases organic acids on rocks hence weakening the rock.
b) i) Identify types of mass wasting marked X, Y and Z.
X—rock fall,
Y—solifluction,
Z--avalanche
(3mks)
ii) Explain two factors that causes soil creep.
(4mks)
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Temperature changes causes expansion and contraction of soil particles hence they
shift position downslope.
Moisture/rain causes particles to be wet, when drying they loosen and shift
downslope.
Human activities/burrowing animals trigger off movement of soil particles
downslope.
Freesing expands spaces between particles on thawing the particles move downslope
by gravity.
Moisture lubricates soil particles hence movement downslope
Moging heavy machines/vehicles/trains trigger down movement of particles..
c) Explain three effects of mass wasting on the environment.
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(6mks)
Mass wasting results to scars on the slopes hence spoiling the scenic beauty.
Movement of materials loosen the top soils facilitating soil erosion.
Landslides block rivers hence formation of temporary lakes.
Landslides may also re-route rivers hence reducing water volume downstream.
Mass movement may cause destruction of properties /loss of lives.
Mass-wasting may create sceneries which attract tourists.
d) A form three class went out for field work on mass wasting. Give three follow up
activities they involved themselves in.
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Class discussion
Displaying photographs
Giving lectures
Making reports.
8. a) Give one fold mountain found in each of the following continents;
(3mks
i) Asia – Himalayas
ii) North America – Rockies/Appalachians
iii) South America – Andes
b) Other than fold mountains, give three features resulting from the process of folding. (3mks)
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Rolling plains
Intermontane plateaus
Intermontane basins
Valleys and ridges
Escarpments
ii) With aid of well labeled diagrams describe how an overthrust fold is formed.
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(6mks)
Rocks on the earth crust are subjected to compression forces.mksmks
Intense fold lead to formation of an overfoldmks
Increased compression results in formation of a recumbent fold
When pressure is very great, a fracture along the axis in the recumbent fold produce a
thrust plane.
The upper part of the recumbent fold slides forward over the lower part along the
plane resulting to formation of an overthrust fold.
Diagram – 2
Text 4
c) Explain four effects of Fold Mountains on humans activities.
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(8mks)
Windward side of fold mountains receives high rainfall which enhance
agriculture/forest
Rivers originating from fold mountains provide water used for
H.E.P/irrigation/domestic/industrial purposes
Some fold mountains have exposed valuable minerals.
Fold mountains attract tourists who bring foreign exchanged.
Fold mountains acts as barriers to communication transport lines.
Steep slopes discourage settlement/agriculture
d) A group of form three student intends to go for a field study on folded features.
i) State three ways in which they would prepare for the study.
 Formulating hypothesis/objectives
 Identifying methods of data collection
 Drawing work schedule
 Carrying out reconnaissance
 Seeking permission from relevant authority
 Sorting tools/equipment
 Assembling stationary
 Reading extensively on the topic
 Diving into groups
ii) Give two advantages of studying landforms through field work.
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Gives first hand information
Application on what is learnt in class to real life situation
Students familiarize with the environment
(2mks)
 Reduce the monotony and boredom in the classroom
 Students appreciate land forms.
 Enhances visual memory/remembrance
9. a) Give three processes that lead to formation of lakes.
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Crustal warping
Volcanic activities
Erosion/ by river/wind/glasier
Deposition/water/ice/river
Human activities
Faulting
Mass wasting
Weathering/solution
Falling meterorites
b) i) Describe how lake Victoria was formed
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(4mks)
Earth movement lead to crustal down warping
A shallow depression was formed
Surrounding areas to the depression underwent uplifting
The uplifting lead to reversed flow of the surrounding rivers
The rivers filled the depression
The resultant lake is known as L. Vitoria.
ii) Explain how L. Victoria influence the climate of the surrounding areas.


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(3mks)
(6mks
Evaporation from the lake leads to formation of convectional rainfall
Evaporation also increases relative humidity
Formation of L. breezes moderate the temperature of the surrounding area/low diurnal
temp range
Causes development reversed local wind in the area
Breezes from the lake bring cooling effects in surrounding areas.
c(i)Apart from L. Bogoria, give two other lake in Kenya with high levels of salinity (2mks
-L. Magadi,
L. Elementaita,
L. Nakuru
(ii) Explain three causes of salinity in L. Bogoria.
(6mks
-It lacks outlets hence salts accumulate in the lake water
-Soluble bed rock dissolves in the lake water
-High evaporation leads to high concentration of salts
-Surface run-off/ rivers deposit mineral salts in the lake hence high concentration in the lake
–Underground seepage of mineral rich water in to the lake hence high concentration of salts
d) Give four economic uses of lakes.
 Lakes attract tourists
 Lakes provide water of domestic/industries
 Lakes act as reservoirs for H.E.P production
 Lakes are used for transport
 Lakes are sources of fish/food
 Sand present in lakes is used for building
10. a) Different between soil profile and soil catena.
(4mks)
(2mks)
Soil profile is the vertical arrangement of soil in layers from top the bedrock while soil catena
is the horizontal arrangement of soil along a slope from top to the base.
b. i) Describe three characteristics of horizon B.
(3mks)
Leached materials from horizon A accumulate here
Texture is clay in nature
Soils are dark/ref/brown in colour
Zone forms hard pan/murram
ii) Apart from humus, name other three components of soil.
(3mks
Soil air
Soil water
Mineral particles
Living organisms
iii) State three ways in which humus contribute to the quality of soil
-iprove soil texture
-provide essential minerals
-enable soil to retain moisture
-facilitate aeration
-provide to micro organisms
© Explain how the following factors influence soil formation
(3mks
i) Time
Where soil formation takes a short time soils are immature/where soil formation has taken a
long time, soils are mature/well developed
(2mks)
ii) Parent rock
Parent rock determines the mineral content of soils
Parent rock determines depth of the soil
Parent rock determines texture
Any 1 x 2 = 2
iii) Topography
Steep slopes encourage removal of soils hence thin soil
Valley bottoms encourage deposition hence deep fertile soils
Flat areas are water logged which slows down soil formation/Gentle slopeshave well drained
soils.
Any 2 x 2 = 4mks
d. Explain how the following farming practices may lead to loss of soil fertility.
i) Overgrazing
(2mks
Encourage removal of vegetation cover hence soil erosion
ii) Frequent ploughing
(2mks
It increases oxidation which result in loss of organic matter
Weakens soil structure hence soil erosion
iii) Continous irrigation
Causes leaching of soil nutrient making top soil deficient of minerals
(2mks