Download KCSE ONLINE GEOGRAPHY PP1 MARKING SCHEME SECTION A

KCSE ONLINE
GEOGRAPHY PP1 MARKING SCHEME
SECTION A
1(a)isohyte;-Is aline drawn on a map to show areas receiving the same amount of rainfall..(1mk)
(b)(i)methods of measuring cloud cover.
-Remote sensing(using computerized camera)
-Estimation by determining what fraction of the sky is covered by clouds. (1mk)
2 parts labeled
-a Troposphere
-b Stratosphere
-c Mesosphere
(b)Importance of Ozone.
-It absorbs Ultra Violet radiation/rays from the sun which are harmful to human life.These
rays cause skin cancer.
3.(a)Differatiate amineral and arock
-amineral is any naturally occurring crystalline inorganic substance with definite chemical
composition and physical properties that form part of the earth;s crust,while
-a rock is any naturally occurring aggregate of mineral particles of the earth;s crust.
(b)Three classifications of igneous rocks.
-Intrusive/plutonic igneous rocks-These are igneous rocks that result from magma which
has cooled at some depth bellow the earth;s surface at slow rate.
-Hypabyssal igneous rocks-These are intrusive igneous rocks which are formed near the
surface of the earth and have cooled at medium rate.
-Extrusive/volcanic igneous rocks-These are igneous rocks that are formed on the surface of
the earth.Lava that reaches the surface of the earth cools very fast.
4(a).Three classification of vegetation.
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-Natural vegetation
-Derived(semi natural)vegetation
-Cultivated vegetation
(b)Two factors influencing distribution of vegetation.
-physiographic/geomorphic factors-which include ,altitude,terrain, drainage and aspect
-Climatic factors-which include temperature,sunlight,humidity,wind.
-Soil/pedological factors-include soil organisms soilair, soil water ,soil texture and nutrients.
-Biotic factors –The effect of animals, plants and people.
5.(a) T hree main types of drainage systems.
-Accordant drainage system
-Discordant drainage system.
-Back-tilted or reversed drainage system.
(b)Desribe a rivers erosion by,
(i)corrosion process
The rocks scooped out of hydraulic action on their way down the stream, hit against the
river bed and banks thereby loosening and dislodging other rocks which are then transported
downstream.This is also called abrasion.
(1mk)
(ii)Solution –Running water contains weak inorganic acids like carbonic acid and humic
acid.They dissolve soluable minerals over the rocks which they flow e.g limestone and dolomite
and carry them down the stream in solution form.This is also called corrosion process.
(1mk)
SECTION B
Answer question 6 and any other two questions from these sections
Q6.Study the map of Nkubu 1:5000 (122/1) provided and answers the following questions
a (i) What was the magnetic variation of the area covered by the map by the time the map was
made (2 marks) 1025´
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(ii) Give the adjoining sheet of Nkubu map to the North East
Nyambene
(iii) Identify to natural features found in grid
-a hill
-a depression
-a forest/trees
-Bamboo
b)(i) calculate the bearing of a church at matiokiama from the school at Kirinyanga To the South
eastern part of the map. (2marks) 3440
(ii)Measure the distance of all weather road bound surface from the northern edge of the map to
where it ends. Give your answer in KM (2marks)
8.4KM +Or-0.1
C (i) Draw a cross section along northing 92 between point 530920to 600920 on your crosssection mark ad name (3marks)
-River Thingithu
-Dry weather road
-Seasonal swamp
Distribution of marks
Title-1mk
Starting point and end point-1mk
Trend-1mk
River-1mk
Labeled y-axis-1mk
Road-1mk
swamp-1mk
TOTAL=7 MARKS
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(ii) Calculate the vertical exaggeration of your cross-section. (2mark)
1/2000 devide by 1/5000 =50/2=25
d.Describe the drainage of the area covered by the map (5marks)
-The area has many permanent rivers
-Rivers generally forms denfuitic drainage system
-Main source of rivers is western side /forest
-Rivers generally flow eastwards
-The main rivers are thingithu and Kithinu.
-There are seasonal swamps to the north-east
-There are lakes to the S.W part of the map.
e. citing evidence from the map identify two crops which are grown in the area (2maks)
-Coffee growing evidenced by the coffee factory
-Tea growing evidenced by tea factory (4393)
7) aiThe diagram below illustrates a composite volcano. Use it to answer question (a)
Name the features marked A, B, and C.
(3mks)
 A Crater
 B Ash/cinder layer
 C Parasitic cone
3 x 1 = 3mks
ii) – Intense heat and pressure pushes/forces molten magna into the interior of the earth.
-
Molten magma flows onto the earth surface through the vent/pipe
Magma cools and then solidify blocking top of volcano
- Successive eruption that follows blows off the top of volcano.
Hollow depression then left behind called crater
5mks
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b) i)
Vulcanicity refers to a process operating in the interior of the earth by which solid, liquid
or gaseous materials are forced out of the interior into the earth’s crust or outer the earth
surface, while volcanic refers to all forms of igneous activity involving material that
reach the surface of earth.(2mks)
ii) – Leads to formation of fertile soil
-
Exposes valuable minerals e.g. diamond,
Stream jet is harnessed e.g. geothermal power e.g. Olkaria
Tourist attraction through formation of volcanic features
Provision of building materials e.g. trachyte etc.
Volcanic mts are river catchments area
Provision of water for industrial and domestic
( 6mks)
ci)An epicenter is a point on the earth surface directly above the focus where seismic waves are
first felt while a focus is a point inside the earth where earthquakes originate
( 2mk)
ii)love waves
Rayleigh waves
c) i)
(2mks)
To assist them avoid time wastages
- Provides an estimate of the time reviewed for study
- Ensures that no activity is left out/forgotten
- Provide a basis for evaluating fieldwork.
- It guides the student to remain with the framework of the field work
(3mks)
ii) – Observation
Photographing
(2mks)
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8(a) What are tides
The periodic rise and fall in sea level.
(1mk)
(ii) Semi diurnal tide occur when both high tides rise to the same level and low tides drop to the
same level.
Mixed tides occurs in pairs with two high tides and two low tides but one pair may fluctuate in
level while the other remain constant.
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(iii) factors that cause horizontal movement of water .
Wind
Earths rotation
Shape of land masses
Differences in water temperature.
(3mks)
Cliff
A deep rock face which border the sea and it may be vertical or nearly vertically.
Form where coast is sloping smoothly but steeply into the sea.
Breaking waves cut a notch on the rock surfaces at the position where waves break at high tide.
The base of rock face continues being undercut by breaking waves while the upper part is
attacked by agents of weathering leading to lowering of upper rock.
If undercutting continous rock may eventually collapse forming a cliff that may then be attacked
by waves forming an overhanging cliff.
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c. cause of coastal emergence
Negative change in base levels
Uplift of coastal land
(2mks)
(ii) Give 3 features of emerged lowland coasts.
Exposed sand spits
Expose bars
(3mks)
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Exposed coral reef
Raised lagoons
Knick point
Differences of fiords and rias 3mks
(i)Rias are funnel shaped whil e fiords are u shaped
(ii)Rias are deeper at the mouth and shallower inland while
fiords are shallower at the mouth and deeper inland
(iii)rias are drowned river valleys while fiords are drowned glaciated valleys
(iii)importance of corals to Kenyan economy 3mks
Coral limestone isa raw material in the cement industry
9a wind action in desert:
-
absence of vegetation cover
presence of loose unconsilidated dry masses of mud, sand and gravels.
the occurrence of strong wind storms in the desert
extensive physical weathering exposes the weatherd rocks to attack by wind erosion
b) deflation
process by which wind eddies scoop out loose,dry unconsoladated materials like dust, fine sand
particles fro the desert surface.
the materials are scooped and lifted up in air
ii) attrition
the materials which are airborne constantly knock against each other and collide thereby
gradually reducing in size into small rounded sand grains
iii) abrassion;
material carried by wind is used to grind, scrape and polish the deesert surface. the
weatherdmaterial knock against rock surface thereby polishing them.
c). deposition features
- sand dunes
- loes
- drass
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d) significance of desert land forms
- sand harvested from desert is used in building and construction.
-oasis attract settlement as they provide domestic water
- desert soil infertile thus hinder agriculture.
- sand dunes are constable and hinder establishment of infrastructure.
- physical weathering exposes valuable minerals which can easily be mined to generate revenue.
-loess/alluvial fans have fertile soil suitable for agriculture.
- desert service provide good military training ground
- Desert surface can be wed for recreation such as the Dakar Motor Rally.
Coral reefs attract tourists earning foreign exchange for the country
Some organisms provide ornamental shells
Coral reefs provide a suitable habitat for a variety of marine life used for education and research.
10a(i)Mass wasting is the movement of unconsolidated material down a slope due to the
influence of gravity
(2mks)
(ii)Mass movement is the movement of unconsolidated materials down a slope after lubrication
by rainwater or snow melt
(2mks)
(iii)Nature of the material e.g weight of the rocks
-Human activities e.g. mining
-occurrence of earthquaskes, volcanic eruptions e.t.c.
-Extent of soil saturation/ amount of rainfall/ precipitation
-Gradient of the land/angle of the slope
-Presence of vegetation
b(I)
(3mks)
M………..Steep slope/cliff face
(1mk)
N…………Talus/talus creep/scree
(1mk)
(ii)Rockfall
(1mk)
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C(i)Weathering is the gradual breakdown and decomposition of rocks insitu(without movement)
(2mks)
(ii)-Frost action-occurs in areas with freezing temperatures.When the temperature rises ice melts
and accumulates in cracks within the rocks.As it freezes water expands and widens the cracks
leading to rock disintegration.
(2mks)
-Pressure release/ unloading-Denudation removes thick layers of soil and thus newly exposed
rocks have less weight on them leading to their expansion hence disintegrating.
(2mks)
(iii)Plant roots grows into joints and cracks which they widen causing rock blocks to disintegrate
-Decaying plant material produce acids which reacts with rock materials causing decay
-Plants like algae,mosses and lichen retain water on rocks resulting to chemical weathering
processes
(4mks)
d(i)To find out the weathering processes dorminant in the area
-To investigate the various uses of weathered material
-To identify the influence of man on weathering in the area
-To find out the vegetation present in the area
(2mks)
(ii)Inaccessibility of some areas due to ruggedness
-Environmental constrains e.g.rainfall
-Unco-operating students
-Hindrance due thick vegetation
-Transport problems
(3mks)
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