common test answers

2016 Elective Geography Common Test Marking Scheme

1		Study Table 1, which shows temperature reading of two cities. City Latitude Altitude Mean annual temperature Balikpapan (Indonesia) 1°16′S 80 metres 27°C Nairobi (Kenya) 1°17′S 1680 metres 18°C
		Table 1
		(a)	With reference to Table 1, explain why Balikpapan and Nairobi experiences different temperatures.                                                                                  [4] -        Although both places has the same latitude, -    their altitude is different as Nairobi is at a higher altitude of 1680m whereas Balikpapan is at a lower altitude of 80m. -        The sun’s shortwave radiation heats up the Earth’s surface and not the air directly -    Therefore, Balikpapan experiences higher temperature as it is nearer to the surface of the Earth. Comments : Most of u did not use Table 1 data (80m and 1680m) to support your answer. Must also note that the latitude is similar. Good ans: Keefe and Darren
		(b)	Describe the steps taken to collect data on relative humidity using a Sling psychrometer.                                                                                                          [5]
-			1.     Dip the wick of the wet bulb in water 2.     Swing the sling psychrometer at steady pace away from body of 2 seconds per turn for one minute 3.     Record the temperature readings and repeat the process if temperature of the second reading is different from the first 4.     Find the wet bulb depression by calculating the difference in wet and dry temperature 5.     Use relative humidity table to find intersection of dry bulb temperature and depression to calculate the relative humidity
-			Comment: Not spin/turn, not graph/chart. Not take average, but take two readings see if it is different. Good ans: Sophiann
		(c)	Using Fig. 1, explain how convectional rain is being formed.                        [4] 1.     The sun’s energy reaches the earth, this heats up the earth’s surface intensely 2.     Air expands, rises and cools, resulting in the increase of relative humidity 3. When it reaches dew point temperature, condensation occurs and Cumulonimbus clouds are formed 4. When water droplets become large and heavy enough, they fall as rain/precipitation

	(d)	Fig. 2 below shows a coast. Complete the diagram to show how a land breeze is being formed.                                                                                                                      [5]
		Fig. 2 -        Arrow from land to sea -        Label ‘land breeze’ -        Land : label ‘lower temperature,  -     Land: 'cool air sinks’ -        Land : label ‘higher pressure’ -        Sea : label ‘higher temperature,  -     Sea : label warm air expands and rises’ -        Sea : label ‘lower pressure’ -        Air moves from high to low pressure -        Night time (Draw moon)             (0.5m each) Full marks: Justin, Nat, Darren
		(e) Describe a suitable location to place a rain gauge and suggest how you will place it.                                                                                                                            [3] Location : Open field with no obstruction Location : Away from tall buildings or trees How to place it:  Sink it into the ground with 30cm protruding above the ground.
		(f)	With reference to Fig. 3, explain why the Northern of Australia receives heavy rainfall.                                                                                                                   [4]
			-        From October to February, Australia experiences summer and is thus an area of low pressure and interior Asia experiences winter and is thus an area of high pressure -        Northeast monsoon wind blows from Asia to Australia from high to low pressure -     After it passes the equator due to Coriolis effect, it is deflected to the left as northwest monsoon -        Warm air picks up moisture and travels over Indian ocean and brings heavy rain to Australia

Good ans: Darren