N level Q5

5	(a)	Annotate Fig. 10 to explain how convectional rainfall is caused.  [4]
		Fig. 10 should have the following information: Sun’s energy reaches the earth The earth’s surface is heated by sun’s energy.  In turn, heats up the surrounding air. Warm air rises and expands Air cools on rising.  Reaches dew point temperature and condensation takes place / condensation level [the horizontal line below the cloud] When the droplets are huge enough, there will be conventional rain, which is followed by thunder and lightning
	(b)	Study Fig. 11A and 11B which show a hygrometer (Sling psychrometer) and a relative humidity table.
	(c)	Using Figs 11A and 11B, state the relative humidity.  Explain how you have used the hygrometer and table to calculate the relative humidity.                                                  [4]
		Relative humidity:  63 % Explanation:  Read dry bulb temperature 25 C; read wet bulb temperature 20 C Find the wet bulb depression; the difference between the dry bulb temperature and wet bulb temperature Read the conversion table to derive the Relative Humidity percentage
	(c)	Study Fig. 12, a graph which shows the average annual temperatures for Singapore over 63 years.
		Describe the trends in average temperatures for Singapore, as shown in Fig. 12.  [4]
		General pattern: Singapore average temperature on the rise/increase Lowest temp: 1975 (26 C) Highest temp : 2000 (28.3) Unique trend : Fluctuation of temperature (temperature sudden increases and decreases) 4@1m
	(d)	What strategies are countries, such as Singapore, developing in response to climate change?                                                                                                                           [4]
		National strategies required:  Singapore Singapore Green Plan 2012 … reduce greenhouse gases by using natural gas as energy Plant-A-Tree Programme … because the trees are green lungs of the environments as they remove carbon dioxide from the atmosphere Green Mark Scheme … construct green building which are energy-efficient and environmentally friendly; such buildings cut down greenhouse gas emissions by reducing the use of fossil fuels to generate electricity Use less energy to provide same service; e.g. using solar energy National strategies required:  India Energy labelling programme … reduce energy consumption by labelling frost-free products like refrigerators, fluorescent lamps and air conditioners, laptops … by using such products there will be energy conservation which helps to reduce nation’s greenhouse gas emissions. National Urban transport Policy … emphasizing public transport … encourage public to take public transport like buses and rail By expanding the rail network, people will take the rail and keep vehicles off the roads and reduce greenhouse gas emissions 4@1m [Can use India’s examples]
	(e)(i)	Describe a tsunami and explain how it is caused.                                                           [4]
		Describe: A huge wave that hits the shore in a short period of time Causes Formed by earthquake in the sea Wave on reaching shallower water, greater friction slows waves and forces waves to increase in height When tsunami reaches coast, speed of tsunami reaches 30 – 50 km/h and height of 15m Reserve 1m – describe a tsunami
	(ii)	‘The impact of a tsunami on people’s lives can be more devastating than that of an earthquakes.’ How far do you agree with this statement?  Give reasons for your answer.                    [6]
		Impact of tsunami Destruction to coastal areas 2004 … 9.2 magnitude earthquake in Indian Ocean, triggered tsunami Damage coastal settlements in 12 countries Most damage to western Sumatra, Aceh. Tsunami … 4- 39 metres high swept 10km inland.  Houses swept away. Impact of earthquakes [any 2 with examples] Disruption to services Fires Landslides Loss of lives and properties

N level 2014 Q4

4	(a)	Study Fig. 8 which shows the East African rift valley and plate boundaries in the area.
		Using Fig. 8, describe the location of the volcanoes and lakes.                                      [4]
		Location of volcanoes At plate boundaries between African Plate and Arabian Plate Along the fault lines of the East African Rift Valley / eastern Africa Mainly in the eastern branch of the rift valley; Less volcanoes in the western branch Location of lakes Within the rift valley Lakes mainly in western branch of the rift valley 4@1m
	(b)	With the help of an annotated diagram, explain how a rift valley is formed.       [4]
		2 continental plates diverge/move apart Tension occurs fractures formed at plate boundary Centre block sinks relative to side blocks Form a linear depression / long depression with steep sides called a rift valley 1m – diagram 3m - explanation 4@1m
		·        As two plates diverge, tensional forces pull rock layers apart in opposite directions. ·        As the two plates continue to diverge, normal faults are created, creating a central mass of rock bounded by the faults, known as a fault block. ·       As the side blocks of land continue to diverge, the fault block in the centre sinks, forming a rift valley.
	(c)	Read the details about Mt Nyamuragira (shown on Fig. 8) and its eruption in 2010, as described in Fig. 9.
		Mt Nyamuragira and the eruption in 2010 Most active volcano in Africa Low silica content of lava Low viscosity of lava Slopes of 3 to 20 In 2010 The lava flowed for 21 km Ash and gas emissions caused health problems Drinking water was contaminated Animals died and crops were destroyed.
		Fig. 9
	(i)	What is the evidence from Fig. 9 that Mt Nyamuragira is a shield volcano?       [4]
		Low silica lava – flows easily and spread over a large area; (elaborate) flows 21 km before solidifying to form a shield volcano (data) suggests that it has very gentle slopes (elaborate) Slopes of 3° and 20° degrees (data) 4@1m If no need to use Figure, differentiate strato and shield by - Height - Slope - Lava (resistance/viscoscity)
	(ii)	Using Fig. 9, explain what risks the volcano presented to the people when it erupted in 2010.                                                                                                                                [4]
		Respiratory problems [ash and gas emissions caused health problems] Ash got into the water courses, turned water into very acidic.  [Drinking water contamination] Destruction of livestock and crops [animals died and crops destroyed] … farmers cannot earn money 4@1m
	(d)	The Red Sea lies on a divergent plate boundary.  Explain the processes taking place at such a plate boundary.                                                                                                     [3]
		2 continental plates move away from each other Creates a fracture/ depression in the earth's crust Forms a linear sea that is elongated in shape 3@1m
	(e)	‘Earthquakes measuring the same magnitude on the Richter Scale cause similar kinds of damage.’  How far do you agree with this statement?  Give reasons for your answer.       [6]
		Same magnitude earthquakes cause similar kinds of damage: Other factors that cause damage earthquake damage: Population density Time of occurrence, i.e. day or night Level of preparedness