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PAPER 1
MARKING SCHEME
Section A.
1. a.) Gutenburg discontinuity is the discontinuity between the mantle and the core.
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It is named after B. Gutenberg who discovered it in 1 915.
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It's a shell consisting of sulphides and oxides
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Mohorovicic discontinuity is between the lithosphere (crust) and mantle, its commonly
referred to as the Moho.
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Named after a Yugoslav Scientist called Nadrija Mohovorici who discovered it in 1909.
(2 marks) *Kyo*
b.)
(i.)
It's a huge sea wave caused by an earthquake occurring in the ocean. (1 mark)
ii.)
Sweeps on land causing a lot of destruction to buildings and loss of life.
>
A strong sea wave may wash away buildings, drowns people and destroy communication
lines.
(1x 2 marks) *Kyo*
2. a.) Area"B"
(l mark) *Kyo*
b.)
In the area lying within the equatorial region the angle of the sun rays is nearly vertical
throughout the year, This means that the heating effects of the suns ray will be maximum
since they are passing through a shorter distance in the atmosphere before striking the
surface and the rays will heat a smaller area.
(3 marks) *Kyo*
3.
(a.)
X- Medial Moraine
(1 mark) *Kyo*
Y- terminal Moraine
(1 mark) *Kyo*
b)
Terminal moraine- it's a long ridge of moraine running across a landscape. It forms at an
ice front
(i.e. at the edges of ice sheets) where it melts.
•
4.a
b.)
5.a
b.)
It's formed when an ice front remains static for a long time forming a ridge of moraine
(about 50 m in height)
c)
i)
Misfits stream or beheaded river
(1mk) *Kyo*
ii)
Presence of: Elbow of capture
•
Wind gap
•
Misfit stream
Knick point
(1x 2 Marks) *Kyo*
•
Benguela
•
Labrador
•
Peruvian
(1x2 marks) *Kyo*
Such ocean currents lower summer temperatures in areas where winds are onshore e.g. Labrador
currents in Canada
•
Moist air blowing over a cold current is cooled and rainfall falls in the ocean and only a ,
cold dry wind gets to land causing drying effects on the adjoining land seen from fact that
adjoining land masses are normally dry.
•
Temperatures are low giving cold chilly conditions
•
The coastline experiences moist and foggy conditions (1X3 marks)
*Kyo*
•
Six's thermometer
•
Hygrometer
•
Rain gauge
•
Wind vane. ;
(1/2 X 4 = 2 marks) *Kyo*
The Six's thermometer and hygrometer would be kept in a wooden box referred to as a
Stevenson screen, to protect the instruments from direct sun rays.
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•
•
A rain gauge should be sited in an open space far away from buildings and trees, because
water drops from trees and buildings would interfere with the amount of rainfall collected
in the jar.
A wind vane should also be sited in an open place so that it can move freely to show the
right direction without any obstacles.
(1X2 marks) *Kyo*
SECTION B
6A)
b.)
c.)
d)
Topographical map, survey map
i.)
R.F scale and linear scale
ii)
Kwale and Kilifi
(1 mark) *Kyo*
( 1mk) *Kyo*
(1 mark) *Kyo*
(1 mark) *Kyo*
iii.)
"0 38' Magnetic variation
297935
Direction
NW.
Bearing.
260°
a.) The distance of the dry weather road-17.7 kilometers (2 marks)
e.) Table measuring 10 X 15CM
SILALONI MSP: 1 : 50,000
(1 mark) *Kyo*
(1 mark) *Kyo*
40
g.)
i.)
ii.)
Ways in which people acquire water
Dams, Water holes Water courses
Possible preparations
Seek permission from relevant authorities
Formulate objectives and hypothesis
Choose suitable methods of data collections
Organize a working schedule
Subdivided themselves into groups
Organize for the means of transport
(2 marks) *Kyo*
(5 marks) *Kyo*
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7.
(i.)
Difference between weathering and mass wasting.
•
Weathering is the breaking down /disintegration of works in-situ.due to exposure
on the surface while mass wasting is the down slope movement of weathered
material under the influence of gravity.
(2 marks) *Kyo*
ii.)
Factors determining weathering
• Relief
• Human activities
• Animals and plants
• Climate
• Structure and texture of rock
(1 x 4 marks) *Kyo*
iii.) How animals and plants contribute towards biological weathering.
•
Moles, rabbits, worms and other animals, which live underground, contribute
towards breaking up of rocks by burrowing.
•
Large herds of animals e.g. wildebeest with their hooves pounding the ground
and breaks it
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They also excrete chemicals substances such as uric acid which when in contact
with the rocks may lead to chemical weathering.
•
Bacteria which is commonly found in the soil secrete enzymes which also
facilitates weathering
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Plants roots particularly those of trees can penetrate through cracks and joints
within rocks.
•
Plants such as algae and lichens assist in keeping the rock surface wet thus
facilitating various chemical processes of rocks disintegration.
•
Plants and decaying vegetation matter also produce acids which can disintegrate
rocks
(2 x 4=8 marks) *Kyo*
c.)
Factors responsible for rapid mass wasting.
Slope (gradient)
Climate
Nature of rocks
Tectonic movements
Human activities.
Weight of materials
Amount of water in materials
(1 x 4 marks) *Kyo*
d.) (i.) types of down wash
Sheet wash/sheet flooding
Gulling
(1 mark) *Kyo*
ii.) Significance of mass wasting
Gullies hinders movement of vehicles and machinery on land
Gullies renders farmland wasted
Rocks that fall can be dangerous to human life
Mass wasting leaves behind a barren rock
Deposits from mass wasting may form good fertile soils for agriculture.
Mounds formed after deposition of materials may block rivers and change their courses.
Some areas of mass of mass wasting have been established as research centers.
Some features of mass wasting are tourist attractions e.g. Avalanches in Switzerland.
(Ix 6 marks) *Kyo*
8. a.) The term rock refers to a hard, solid compact mass found on the earth crust, which is a
combination of different minerals.
(2 marks) *Kyo*
b.)
Characteristics of organically formed sedimentary rocks.
They consist of calcarerous rocks ferruginous rocks, siliceous rocks,
carbonaceous rocks or.
Organically formed sedimentary rocks are formed by the accumulation of animal
and plant remains in lakes, seas, oceans or are buried on land.
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-
Calcareous rocks are rich in calcium carbonate formed from skeletons of dead
organisms e.g. limestone rock
Ferruginous rocks are formed in marshes and lakes by the precipitation of
hydrated iron oxide from water, a process associated with minute bacteria
released by decomposing vegetation e.g iron stone.
*
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Siliceous rocks are formed by the accumulation of remains of organisms such as
sponges and diatoms that are rich in silica, found in places which were once under
water but at present dry. An example of siliceous rocks is diatomite.
Carbonaceous rocks are formed from the accumulation of plants which have been
under pressure a sequence referred to as coal series ( from peat, liginite (brown coal)
.bituminous coal (soft coal) and anthracite (hard coal)
(2 x 5 = 10 marks) *Kyo*
c.) The type of rocks marked
A- Sedimentary rocks
(1 mark) *Kyo*
B- Igneous rocks
(1 mark) *Kyo*
C- Metamorphic rocks
(1 mark) *Kyo*
d.) Uses of rocks in Kenya.
•
Mineral deposits -different types of rocks contain valuable minerals e.g.
gold occurring in veins in igneous rocks
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Building materials- some some provide useful materials for building e.g Slate is
useful for roofing materials, sandstone gramnules dolerite, gabbro etc. For
building house, roads etc.
•
Fertile soils- all types of soils come from rocks as parent materials.
Rocks are weathered to produce soils, volcanic rocks when weathered
yield fertile soils.
•
Tourist attraction - some rocks have unique appearances and attract local and
international tourists e.g. the granite rocks in western Kenya.
•
Chemical - some sedimentary rocks contain salts such as nitrates and phosphates;
such salts are used for the manufacture of fertilizers, dyes and medicines.
•
Water supply- rocks affect the circulation of ground water that sink ,, through
them. The permeability of rocks determines the amount of runoff that feeds rivers,
likewise to the water stored in man made dams. (2 x55= 10 marks) *Kyo*
9. a.) Aquifer is a water bearing rock
(1 mark) *Kyo*
b.) A well is a pit sunk into the ground to below the water table. Wells sunk below the water
table will always contain water while those dug up to the water table may dry up in the
dry season.
•
A spring is a water flowing out on to the surface naturally formed when an
aquifer outcrops to the surface, may be seasonal or permanent, seasonal ones occur
during the wet season, while permanent ones occur throughout the year, spring water
may form a stream or river.
(2-X 2 = 4 marks) *Kyo*
c)
Factors that influence the formation of springs.
•
When a permeable rock lies on top of an impermeable rock
•
When water enters the rock through the joint ,springs often occurs where
the water table meets the surface.
•
If a dyke cuts across a layer of permeable rock when water on the up slope side of the
dyke is trapped. This causes the water table to rise and springs develop where water table
meets the surface.
•
When chalk or limestone escarpment overlies impermeable rocks, the
spring usually develops at the bottom of the scarp where the water table meets the
surface.
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d.)
'
•
When rain falling on the exposed ends of the permeable rock soaks down the
sloping bedding planes a spring may emerge. When limestone rocks, overlie impermeable
rocks, springs develop along the functions of the rocks.
(2 X 3=6 marks) *Kyo*
Importance of underground water.
- Provide site for settlement
- Water from wells are used for irrigation in dry lands
- Spring from a major source of water for both domestic and industrial use,
- Spring from source of rivers especially in highlands
- Hot springs deposit some minerals especially salt particles.
- Hot springs are tourist attractions
- Generates geothermal energy (from hot springs/geysers)
(IX 5= 5 marks) *Kyo*
e.) i.) To find out the different ways in which springs are formed in the area of study.
- To examine how springs are used by residents of the area and the school
ii.) Content Analysis.
- This would involve reading published and unpublished reports on the
distribution of springs in the study area e.g. geological reports. magazines, books.
notes, written in the field which may be used in preparing field work reports.
- Direct observation-involves looking at the distribution of spring and
writing down of notes
iii.) Information available in published or unpublished reports may be inadequate or
inaccurate.
- Residents of the area, where the field study is carried out may be hostile and may not
allow students to trespass on their lands.
- Area may be inaccessible due to rugged terrain, rainfall etc.
- Hostile climate-could be rainy, foggy etc.
- Accidents- students falling and getting injured, bitten by wild insects, snakes or
attacked by wild animals
(1 X 3= 3 marks) *Kyo*
10. (i.)a)vegetation zones
B- Bamboo forest
C- Tropical rain forest
D- Savannah vegetation.
(1 X 3= 3 marks) *Kyo*
ii.)
The place is too high for vegetation growth
o
Area covered by snow/ice
o
The zone has extremely low temperatures thus preventing vegetation growth
o
Bare rock preventing vegetation penetration
b.) i.) The grasslands marked
V- Steppe,
W- Prairies,
X- Veld,
Y- Pampas,
Z- Downs
ii.) Characteristic of savannah vegetation
Grassland with scattered trees due to moderate rainfall
Characterized by umbrella shaped trees to prevent intensive heating thus reducing the
rate of evaporation
Consist of trees with long roots to tap water from deep underground
Trees shed leaves during dry seasons.
Some have no leaves/thin leaves/spiky/waxy/needle shaped like leaves to reduce
transpiration.
Some plants have thick/fleshy/succulent leaves/barks to help store water.
Some plant seeds can remain dormant for a long time awaiting the start of rains
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c.)
i.)
ii.)
i'fpl- .
#,;.
Some plants may wither or dry up in absence of rain or moisture but have the ability of
quick recovery
(2 X 4= 8 marks) *Kyo*
Other activities to carry out during the field study.
Measure/estimate distance/heights
Collect samples/transect
Record/take notes
Take photographs of plants/area
Count the plants.
(1 X 3 = 3 marks) *Kyo*
How do I identify different plants.
By looking at the appearance
By looking at the colour
By looking at their leaf size/pattern/type.
By looking at their age
By looking at their barks
By looking at the texture of their leaves
By looking at their root system
By looking at their flowers/fruits
By looking at their height
(1X3 = 3 marks) *Kyo*
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