Sunday, August 30, 2015

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

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