What is an eclipse? (2mks)
- It refers to a shadow resulting from the blockage of the sunrays from reaching the earth or the moon’s surface.
State three effects of the earth’s rotation. (3mks)
- It causes the occurrence of day and night.
- It causes periodic rise and fall of ocean tides
- It causes a time difference between longitudes
- It causes variation of atmospheric pressure on the earth’s surface.
- It causes deflection of winds and ocean currents
- What is an eclipse? (2mks)
The diagram below shows the structure of the earth. Use it to answer the questions that follow
Name the parts marked E,F, and G (3mks)
F – Inner core
Describe the characteristics of the part labeled H. (4mks)
- It has two layers namely upper mantle and lower mantle
- The lower mantle has a temperature of about 3000
- The upper mantle is elastic solid while the lower mantle is molten
- The average density is about 3.3gm/cm3
- Name the parts marked E,F, and G (3mks)
Identify the three forms of metamorphism. (3mks
- thermal metamorphism
- dynamic metamorphism
- thermal dynamic metamorphism
Give the metamorphic equivalents of the following rocks (4mks)
- Granite - Gneiss
- Limestone - marble
- Quarts - quartzite
Coal - graphite
- Identify the three forms of metamorphism. (3mks
What is a seismic wave?
- It refers to shock waves which originate from the starting point of an earthquake moving outwards in all directions.
State four ways in which earthquake affects human activities. (2mks)
- causes loss of lives and destructions of property
- They occasionally trigger fires hence the occurrence of fire.
- Resultant landslide have a direct impact on plants and animals
- Earthquake can tear apart man made facilities such as bridges, roads, railways, gas pipes, etc causing transport and communication problems.
- lowering of land near the sea or rising of the sea floor cause flooding when it occurs suddenly
- Construction of tall buildings is limited in areas prone to earthquakes thus restricting growth of towns
- Generally weaken existing structures causing panic to residents of an area.
- What is a seismic wave?
Define faulting. (2mks)
- it refers to fracturing or cracking of crustal rocks
Describe how the following features are formed
Rift valley (6mks)
- Layers of crustal rocks are subjected to tensional force leading to the formation of normal faults.
- Continued tensional forces cause the middle block o subside tearing the outer block of the same level
- The sunken or the subsided middle block forms a depression called a rift valley, while the sides are the escarpments.
Caldera by violent eruption. (4mks)
- Vent eruption leads to the formation to the formation of a volcanic cone.
- After a period of calm, the vent is sealed leading to the development of intense pressure beneath the volcano.
- Later, a more violent eruption occurs which destroy the top head of the volcano,thus forming a large depression called a caldera
- Rift valley (6mks)
State four negative effects of vulcanicity on human beings. (4mks)
- The leeward side of the volcanic mountains are dry thus discouraging agriculture.
- Volcanic features are rugged thus hinders transport and communication
- Recent lava flows cover fertilizer soil thus discouraging agricultur
- Ash particles resulting from vulcanicity form a blanket in the upper atmosphere thus lowering global temperatures.
- Emission of volcanic gases such as sulphur dioxide cause pollution
You are planning to carry out a field study on features formed by vulcanicity on the landscape.
- Give two methods you would use to collect data. (2mks)
- Content analysis
- Administering a questionaire
State two problems you may face during the field study. (2mks)
- Fatigue due to long distance of walking
- Snake or insect bit
- Abrupt stop of the study due to heavy rainfal
- Give two methods you would use to collect data. (2mks)
- Define faulting. (2mks)
State four ways in which minerals may occur. (4mks)
- some occur in seams or layers
- some occur as weathering products
- some minerals occur as allurial deposits.
- Others occur in vein or lodes
- Other than deep shaft method, name two other underground methods of mining. (2mks)
Describe how deep shaft mining method is carried out.
- A deep shaft is sunk underground up to the level of the mineral
- Horizontal tunnels are dug to reach the mineral ore
- Vertical beams are erected to support the roof of the tunnel.
- Light railway lines are laid down in the tunnels for transporting the ore up to the base of the shaft.
- The ore is hoisted to the surface using electrically driven pulleys to be transported to the factory for processing.
Explain two ways in which Kenya has benefited from the mining of soda ash from Lake Magadi. (4mks)
- It has led to the growth of magadi township
- It has led to the development of social amenities such as hospitals
- It has stimulated development of transport routes from Konza to Magadi.
- It has encouraged the development of industries by proving raw materials eg glass industries
- It has provided employment to many Kenyans thus improving their ling standards.
State four adverse effects of gold mining to the environment of South Africa. (4mks)
- It has left the ground bare resulting to soil erosion
- It has caused instability of the basement rock
- It has resulted to land and water pollution
- It has resulted to wastage of agricultural land.
- It has restricted biodiversity
- It has disrupted or lowered the water table
- It has left the land derelict.
- State four ways in which minerals may occur. (4mks)
Define weather (2mks)
- it refers to atmospheric weather condition of a place at a particular time
Give any three elements of weather apart from humidity. (3mks)
- atmospheric pressure
Describe how humidity is measured in weather station. (4mks)
- measure and record dry bulb thermometer reading
- measure and record wet bulb thermometer
- calculate the difference between the
- Interpret the difference
- If the difference is Zero then the air is saturated with moisture, if its smaller then humidity is high and if its is large the humidity is low
- Define weather (2mks)
Define weather forecasting. (2mks)
- It refers to the prediction of the atmospheric conditions of a place over a specific time period.
State four importance of weather forecasting. (4mks)
- it provides a guide for fishing activities
- it helps in planning for military activities
- it enable farmers to plan their farming calendar of events
- it influences the design of houses
- It provides a guide in landing and take off as well as ocean/marine travels.
- It helps in the choice of clothing for the day
- It helps in the preparedness in relation to weather disasters
- Define weather forecasting. (2mks)
Define folding. (2mks)
- It refers to crustal distortion causing the crustal rocks to bend upwards and downwards .
Give three types of folds. (3mks)
- Symetrical fold
- Assymetrical folds
- Overfold fold
- recumbent fold
- Isoclinal fold
- overthrust fold
- anticlinorium and synclinorium complex
Apart from Fold Mountains, give two other resultant features of folding. (2mks)
- Inter-montane plateaus
- inter – montane basins
- isoclinical valleys/ridge and valley landscape
- Rolling plains
With the help of well labeled diagram describe how Fold Mountains are formed (8mks)
- Earth movement may lead to the formation of a geosyncline on the earth’s surface.
- The geosyncline is filled with water and sediments due to erosion in the surrounding higher ground
- Accumulation of sediments to great thickness causes the geosyncline to subside or sink further.
- The subsidence of the geosyncline triggers compressional forces in the sedimentary rock layers to fold forming fold mountains
- Apart from Fold Mountains, give two other resultant features of folding. (2mks)
Explain the effects of folding on physical and human environment (8mks)
- Folding leads to the formation of fold mountain whose windward side experience high rainfall which favour agriculture and forest growth.
- Resultant features of folding such as fold mountains are tourist attraction earning income.
- Fold mountains are river sources which provide water for agriculture, hydroelectric power generation, industrial and domestic use.
- During folding process some minerals are brought close to the surface thus encouraging mining/ some minerals are buried deep beneath the surface thus discouraging mining.
- The leeward side of fold mountains experience low rainfall which encourage pastrolism but discourage crop farming
- Define folding. (2mks)