P51 and P68 and P41

P51

Outline why there are volcanoes at plate boundary Y.                                                             [4]

1 mark for each of the following points:

·         Oceanic-continental convergence between the Nazca Plate (oceanic) and the South American plate (continental)

·         When the oceanic plate converges with the continental plate, the denser oceanic Nazca plate subducts beneath the less dense continental South American plate.

·         **not necessary (An oceanic trench is formed at the point fo subduction and fold mountains form on the continental plate.)

·         At the subduction zone, solid mantle material melts and forms magma.

·         The magma rises through the crust, giving rise to volcanoes and volcanic eruptions.

P68

BEDOK NORTH SECONDARY SCHOOL PRELIMS 2014

20     Describe the likely effects of the earthquake on the people and the landscape in the area.      [5]

                                                                                                                                 

·         The tremors would result in the destruction of the infrastructure of the area such as dam and roads.

·         Due to the high population density of the city, the extent of damage may be devastating as it will cause many lives to be lost.

·         There could also be loss of lives due to landslides from the nearby mountain.

·         Due to the tremors, the gas pipes may be damaged and thus there might be a likelihood of fire.

·         Electricity cables may be also damaged and thus communication services such as television broadcasts and telephone lines may also be affected. 

·         Destruction of homes/ settlements as the large city is very near the fault lines.

P41

Use Fig. 9 to contrast the rainfall patterns of the two climates.

·          TEC has higher rainfall than TMC (total annual rainfall of 2365mm in TEC and 1490mm in TMC). ·          TEC wet throughout the year while TMC has a distinct wet and dry season (TEC at least 100mm of rain monthly while TMC has dry season from Jan to May, Nov and Dec but wet season from Jun to Oct). ·          Wet months for TMC have higher rainfall than those for TEC (>300mm in Jul and Aug in TMC while around 270mm in Apr, Oct and Nov in TEC). ·          TMC is especially wet in middle of the year (Jun to Sep) but during the same period, TEC rainfall is the lowest. ·          End of the year is dry months for TMC but high rainfall experienced in TEC. [3m for any 3 points] *

P7,8

Using information from Figs. 3 and 4, explain whether the hypotheses are supported and how the experiment could be improved.                                                                           [5]

·        Hypothesis is supported as wind is mostly southwest. ·        The second hypothesis is not supported, as the presence of wind does not always lead to a decrease in temperature.                                            (Max2@1 mark) ·        Data could be collected over longer hours to provide more data points. ·        Data could be collected at more sites to provide data points. ·        Data could be collected over the entire June to provide allow data averaging. ·        Reading of temperature could be done by one student to prevent parallax errors.                                                                                                  Max3@1 mark

Construct a wind rose that shows the wind direction from 0900 to 1400 at the basketball court.                                                                                                                                [2]

Name the instrument that the students could have used to identify wind direction and describe how to use the instrument.                                                                                [3]

·        Wind vane ·        Place the wind vane in an area or manner such that the wind vane is not obstructed. ·        Record the direction of the wind as where the wind vane points to.

Using graph paper, plot a line graph each to show the temperature of the open field and basketball court and explain the usefulness of using line graphs to present data.          [3]

Award 1mk each for each correctly plotted line graph. Usefulness: Shows trends over time. Allow for easy comparison of multiple sets of data. May be used to estimate future patterns. Max1@1 mark

P2,3,5

Using Fig. 1, suggest another suitable hypothesis for the class to investigate.

·        Relative humidity is affected by the type of ground surface ·        Temperature is affected by the type of ground surface                 Accept any other plausible answer

Using Fig. 1, identify the instruments needed in this investigation.

·        Digital thermometer ·        Hygrometer                1m each

Suggest three reasons why temperatures vary around the school campus.

·        Buildings / tarmac / concrete absorb / store heat from sun or internal heating system ·        Buildings radiate heat for small distance around them thus temperatures are higher nearer to buildings ·        Aspect / south facing / north facing / faces sun will have higher temperature ·        Sun: shade from sun/ shade by trees / buildings will have lower temperature ·        Wind: Shelter from wind / exposure to wind / shelter by trees/ buildings will result in different temperature ·        Different types of surface / e.g. some on grass and concrete                 1m each P3 Do you think the Hypothesis "Temperatures are higher nearer to buildings " is correct? Support your answer with evidence from Fig 1. [3] ·         Yes / hypothesis is correct / partially correct / temperatures are higher near buildings ·        temperatures are lower away from buildings ·        Three highest recordings are all next to / within 3m of buildings (C, E, H) ·        Three lowest recordings are all far away / more than 30m from buildings ·        Comparison between sites e.g. Site (E) at 1 m is 28.9oC but site (F) at 17m is 28.2 oC ·        Alternatively highest temp (at C) which is near buildings / lowest (at M) which is furthest from buildings – 1 max ·        More than 20 m away, temperatures are below 28.3oC ·        Anomaly (e.g. B is within 3 m but lower temperature than other sites) – must say why it is an anomaly – 1 max    P5 d.   The students reached the conclusion that the hypothesis: Relative humidity is affected by the type of ground surface was incorrect. Use evidence from Fig. 4 and Fig. 5 to support their conclusion.                                                                                                                                                     [4] ·     Small range in variation / no obvious pattern ·     Relative humidity is similar over the campus and even across different surfaces. ·     For instance, the variation in relative humidity is between 73 and 77 %. ·     There is only a 4 % difference for all the six surfaces. ·     The same reading of relative humidity at 73% is recorded at these surfaces: grass, concrete, trees, tarmac. ·     Even on concrete surfaces, different relative humidity readings of 73, 76 and 77% are recorded. e.       Explain how relative humidity readings can be used.                                                                 [3] ·     Tells us the amount of moisture in the air compared to what the air can actually hold at that temperature. ·     A relative humidity value of 100% would indicate that saturation is reached. ·     Thereafter, condensation would occur. Award 1 mark for each description and other plausible answers P ng P

P16,17

	(a)		Explain why desire lines are a good method to map the length of stay.	[2]
			They show the actual country of origin and destination of movement. The thickness of the lines is proportional to the average length of stay of tourists in Mauritius.
	(b)		Explain the limitations of using a desire line map.
			·   They lack precise interpretation of data. ·   Lines may overlap and hinder the accuracy of reading the map. ·   Does not show changes in average length of stay over time. ·   Arrows become congested. (accept any other possible answer)	[2]
	(c)	One student thought that the average length of stay of tourists may be linked to how far away their origin was from Mauritius.                                                                                                                                 State how this relationship could be expressed and plot a scatter graph to show the relationship using Switzerland, India and South Africa as examples.                                                                              [4]

D) REFLECTIVE THINKING

The students also asked visitors the reasons why they chose Singapore as a holiday destination during the survey conducted.  The results of their findings are shown in Table 5.

Reasons why visitors chose Singapore as a holiday destination

Reasons	No. of visitors who agree	No. of visitors who disagree
It is easy to travel around Singapore.	50	0
Travelling in Singapore is affordable.	9	41
There is a lot to see and do in Singapore.	22	28

Table 5

(d) With reference to Table 5, suggest the conclusion students can make about the main reason why tourists chose Singapore as a holiday destination and one way they can improve the survey to get more reliable data.                                                                                              [3]                                                                                                                                                                               

Reserve 1 mark for conclusion and 1 mark to support (2 marks):

·       Students can conclude that the main reason why tourists chose Singapore as a holiday destination is the easiness of travelling around the country.

·       Highest percentage / All visitors interviewed agreed to the statement ‘It is easy to travel around Singapore’.

1 mark for any plausible way to get more reliable data (any of the points below, each point 1 mark each):

·       The students should interview a larger number of visitors from various tourist origins.

·       The students should conduct their interview at different times of the day.

·       Provide more reasons / have open-ended questions