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TESO SOUTH DISTRICT JOINT EVALUATION TEST Kenya Certificate of Secondary Education (K.C.S.E)

312/1

GEOGRAPHY

Paper 1

JULY/AUGUST 2012

MARKING SCHEME

SECTION A

1. a) Give the name of the force responsible for the:

i) Flattening at the poles of the earth. (1 mark) - Centripetal

ii) Bulging at the equator. (1 mark) - centrifugal

iii) Rounding shape of the earth. (1 mark) - Gravity

b) Highlight two reasons why the interior of the earth is still very hot. (2 marks) - The original heat is still retained

- Radioactivity

- The weight of the crustal rocks

2x1=2 marks

2. a) What do you understand by the term green house effect? (2 marks) It is a naturally occurring process that aids in heating the earth’s surface and atmosphere

Or

A condition where the incoming solar radiation pass through the atmosphere while the

outgoing terrestrial radiation is blocked by gases/clouds in the atmosphere making the

earth warmer than it would have been

The process where atmospheric gases such as carbon dioxide, methane, nitrous oxide,

chlorofluorocarbon(CFCs) ozone and water vapour are able to change the energy of the

planet by absorbing terrestrial radiation.

b) Give twp reasons why some weather recording instruments are stored inside a

Stevenson screen. (2 marks) - To provide the shade conditions required for accurate temperature reading

- To ensure safety and protection of delicate instruments

2x1=2 marks

c) Name an instrument kept in Stevenson screen. (1 mark) - Maximum and minimum thermometer

- Hygrometer

- Six’s thermometer

- Barometer

3. a) Differentiate between eluviations and salination in soil. (2 marks) Eluviation refers to leaching of minerals from horizon A to B to C whereas salination

refers to the upward movement of water and the drying of soil forming a thin salty crust on

the surface.

(Must include word-while, whereas etc to score)

b)

Study the diagram above and name the parts marked A - Humus (1 mark)


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B - Sub-soil (1 mark)

C - Parent rock (1 mark)

4. a) Define the term weathering. (2 marks) The breaking, disintegration and decay of solid rock at or near the earth’s surface in sit by

physical and chemical processes

1x2=2 marks

b) State three chemical weathering processes. (3 marks) - Carbonation

- Hydration

- Solution

- Oxidation

- Hydrolysis

Any 3x1=3 marks

5. a) What is an artesian basin? (2 marks) Is the stratum in the earth’s crust in which one or more aquifers are enclosed above and

below by an unpermeable strata.

b) State three conditions that favour the location of the artesian well. (3 marks) - The aquifer must be semi permeable materials

- The aquifer must be explored in an area of sufficient precipitation

- It must lie in between two impermeable rocks for it to retain water

- The basin must dip towards a region where the land surface is lower than it is

exposed end of the pervious formation

- There must be a partial construction or total blockage of exit sufficient for the

water that comes in higher portion of the aquifer to be replaced under pressure

SECTION B

6. a) i) Give the four and six figure grid reference of cattle dip near Nkuene school

(1 mark) - 4-figure GR-4196� 1 mark

- 6-figure GR-416966� 1 mark

ii) What is the bearing of the air photo principal point near Kagwa mpungu from

Kieru coffee factory? (2 marks) 116

0

1x2=2 marks

iii) In reference to the marginal information given in the map, what was the

magnetic variation in the year 1977? (2 marks)

1975⇒1025

I

1977⇒1025

I-10

I �

1015

I �

b) i) Describe the settlement in the area covered by the map. (3 marks) - No settlement in the forested areas

- Dispersed settlement

- Areas around swamps under settled

- Linear settlement major roads

- Nucleated centres around urban centres e.g NKubu

- South eastern part of the areas covered by the map is sparsely settled

Accept any other relevant point 1x3=3 marks

ii) Citing evidence from the map, explain three factors that have favoured coffee

farming in Nkubu are. (6 marks) - Existence of numerous coffee factories-factories


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- Forests indicative o fhigh rainfall in the place

- Well drained soils-close contours and many rivers

- Cool temperature-high altitude above 1000M above sea level

- Availability of transport-Network of roads all over

Accept any relevant point 1x3=3 marks

N.B No evidence no marks

c) i) Using a vertical scale of 1 cm draw a cross section from grid reference 378905

to grid 429942. (5 marks)

ii) On the cross section draw, mark and name the following.

- A hill (1 mark)

- Secondary trigonometric station (1 mark)

- A loose surface road. (1 mark)

iii) Calculate the vertical exaggeration(V.E) of the cross section. (2 marks)


4

5.2.

1

000,50

000,20

1

000,50

1

100200

1

000,50:1

2001.

.

.

=

×=

÷

×

=

=

=

=

EV

mrepcmEV

ScaleHorizontal

ScaleVerticalEV

EquivalentHorizontal

ScaleVerticalEV

7. a) i) What is a desert? (2 marks) - It is a barren/unproductive land with sparse vegetation

or

- An area that receive low or unreliable rainfall and has sparse/scanty

vegetation

ii) State three characteristics of desert landforms. (3 marks) - Partial or absence of vegetation

- Almost complete absence of water

- Surface is stoney/rocky and sandy

- Mechanical weathering is dorminant

Any 3x1=3 marks

iii) State three factors that contributed to the development of deserts.(3 marks) - Insufficient rainfall i.e less than 250mm per annum

- High temperature leading to high evaporation rates

- Cold ocean currents offshore which flow across the path of onshore rain

bearing winds

- Relief barriers-Presence of high mountains which block rain bearing winds

causing a rain shadow

- Continentality-remoteness of land in the interior of a continent far away

from direct influence of the sea

- Pressure system-location of an area in region of anticyclones where where

wind are descending and diverging

- Human activities suc as deforestation, overgrazing and overdrawing of

underground water

Any 3x1=3 marks

b) i) Explain three factors that influence wind deposition in desert. (6 marks) - Obstacles on the path of wind will reduce velocity and cause deposition

- Presence of precipitation may force wind to deposit the load

- Strength and velocity of wind, weak winds may be unable to carry its load

hence deposit

- Amount of load, if load is heavy, it is likely to be deposited faster than light

loads

- The nature of the desert land surface

Any 3 well explained x2=6 marks

ii) State three ways in which wind erosion take place in deserts. (3 marks) - Abrasion


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- Deflation

- Attrition

Any 3x1= 3 marks

c) Use the map below to answer the following questions.

Name the desert marked K, L and M. (3 marks) K-Atacama

L-Namib

M-Gobi

d) With the aid of a well labeled diagram, describe how a yardang is formed.(5 marks)

8. a) i) Differentiate between an ice cap and an iceberg. (2 marks)

- An icecap is a small but permanent mass of ice covering a limited area of

plateau or mountain top while an iceberg is a floating mass of ice that has

broken away freedom an ice sheet at the edge of the sea

Mark as a wholex2=2 marks

ii) Account for lack of ice sheets in Kenya. (2 marks) - Temperatures are high because Kenya is within the tropics

- Much of Kenya is not high enough to develop ice.

1x2=2 marks

iiii) Explain three factors that influence glacial erosion in highlands.(6 marks)


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- Nature of the underlying rock

- The speed of the glacier

- The thickness and weight of the ice

- Availability of debris

b) Describe how an arête is formed. (4 marks) - Snow collects in hollows on the mountain slopes-changes to ice and slides slowly

forwards

- Water freezes in winter-expands and forces cracks to open

- Eventually pieces of rocks break way and freeze into glacier

- Plucking-roc freezing into glacier here, striating or scaping to depen basin as rocks

carried forward

- Steep jagged edge of mountains is formed(arête with steep back and side walls

Any 4x1=4 marks

c) The diagram below is a glacial feature in lowland.

i) What is the direction of the ice? (1 mark)

The direction of the wind is eastwards

ii) Name the pats F and G. (2 marks) F=Head 1 mark

G=Tail 1 mark

d) Form 3 students of a school in Kenya intend to carry out a field study on glaciations.

i) Suggest two possible areas of study they would visit in their country.(2 marks) - Mt. Kenya

- Mt. Kilimanjaro

ii) State three ways in which they would prepare for the study. (3 marks) - Reconnaissance

- Assemble equipment

- Library research

- Development of route map

Any3x1= 3 marks

iii) What problems are they likely to encounter in this kind of study?(3 marks) - Accidents


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- Low temperatures

- Dangerous animals

9. a) i) Differentiate between derived vegetation and natural vegetation.(2 marks) Derived vegetation exists naturally but has been interfered with by people while

natural vegetation is the plant cover that exists naturally in ann area without any

external interference or modification by people or animals

ii) Explain three ways in which human activities have influenced distribution of

vegetation in Kenya. (6 marks) - Clearance for roads, settlements, industrial centres, mines etc

- Bush fires

- Overgrazing

- Shifting cultivation

- Nomadic pastoralism

Any 3 well explained point x2=6 marks

b) Name the temperate grasslands found in the following countries: - Canada - The prairies (1 mark)

- South Africa - Veldt (1 mark)

- Argentina - Pampas (1 mark)

- Australia - Downs (1 mark)

c) Study the map below and answer the following questions:

i) Name the vegetation zones B and C. (2 marks)

B-Scrub and desert vegetation

C-Mountain forest

ii) Highlight four characteristics of the vegetation type marked A.(4 marks) - Occur in poorly drained areas, swamps


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- May occur in places experiencing periodic rains

- Vegetation adapted to waterlogged conditions

- There is a variety of plants with papyrus dominant

- Others include marshes and grasses with smooth surface and long blades

- Trees are not common in water logged conditions

d) You are supposed to carry out a field study on the uses of vegetation around your

school.

i) Give three reasons why reconnaissance is necessary. (3 marks) - To plan work route

- Try to foresee problems

- Seek official permission

- Identification of appropriate equipment and materials

- Familiarization of the area before study

Accept any relevant point 1x3=3 marks

ii) Give four uses of vegetation you are likely to identify during the study.

(4 marks)

10. a) i) Define the term tsunami. (2 marks) Huge sea waves that occur when volcanoes erupt in sea bed or when earthquakes

occur in sea. (2 marks)

ii) The diagram below shows the mechanisms of earthquakes

Name the parts labeled P, Q and R. (3 marks) P-Epicentre

Q-Seismic focus

R-Surface wave

b) i) Using illustrations, describe three types of earthquakes waves. (9 marks) Primary waves

- Primary causes rock particles to vibrate in a push and pull manner

- Passes through liquids, gases and solids

- They are the fastest vibrations recorded first

Direction of propagation


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Secondary waves

- Causes rock particles to vibrate at a right angle s to the direction of the

wave movement

- They only pass through solids

- They are recorded after primary waves

Longitudinal waves

- They are very destructive

- Cause surface rocks to shake making buildings to collapse

- Particles move either in elliptical manner or in a horizontal and at right

angles to the surface of the wave

ii) Explain four proofs that the crust is in constant movement. (8 marks)

- Sea floor spreading

- Formation of fold mountains

- Formation of transform fault

- Formation of land forms

Any 4x2=8 marks

c) State three ways in which the earth’s crust is affected by the earthquakes.(3 marks) - Causes landslides

- Causes faulting

- Causes volcanic erruptions


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END

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