RVHS Prelim H2 GEO P2 Soln

1 RVHS H2 GEOGRAPHY PAPER 2 PRELIMS 2018 1 (a) Suggest a suitable research question for this investigation about infiltration rates. [1] Key criteria: 1. clearly defined 2. capable of being researched 3. situated within manageable spatial and/or time scales Award 1m for any suitable research question. No marks if a hypothesis statement is given. e.g. How do raingardens impact infiltration patterns in urban areas in the tropics? (b) With reference to Resources 1 and 2, explain two potential risks associated with carrying out this geographical investigation and how the group might minimise each risk. [4] ‘Risk’ is defined as the threats to welfare and danger to life for the investigators. In the context, these may include: - Dangers associated with traffic because of proximity to the roads - The canal as a source of danger - Weather related risks (thunder storms, high mid-day temperatures) Award 2m for each elaborated risk and proposal for precautionary measures (c) Referring to Resource 2, explain how the students used the equipment to measure the infiltration rate at a data site. [5] 1. Operational steps to using the double-ring infiltrometer and explanation of rationale a) Plunging infiltrometer up to limit of the ring lid b) Filling the outer ring to prevent lateral diffusion of water c) Filling up to a standardised level and noting the fall in water level on the ruled markings on the infiltrometer for a standardised time. d) Refilling to the same level and repeating the measurement of water level fall in a standardised time (to maintain standardised pressure on the soil) for the number of times necessary 2. Precautionary principles (minimial disturbance of soil structure, timing and reading) a) Taking care to clear the sample site of irrelevant debris like rocks and litter which might compromise readings b) Minimising disturbance of soil structure by single, clean action of inserting the infiltrometer c) Avoiding parallax error by ensuring perpendicularity of the infiltrometer Point Marked: Award max 3m for pure description of steps without rationale (d) The students reflected that the findings might have been compromised by intervening factors. With reference to Resources 1, 2 and 3, discuss how the process of data collection could be improved. [7]

2 Indicative content: Intervening factors affecting accuracy / credibility of data: 1) Separation of data collection into 2 sittings compromises the comparability of the data collected. Ideal situation would have been collecting all data within the same sitting to ensure that relevant conditions like antecedent soil moisture are the same 2) random sampling might not have been the most suitable method for ensuring that the range of data collected is representative of the types of surfa ces found along segments A and B respectively (many types of surfaces) 3) Difficulties of measuring in a planted bed Suggestions for improvement: - Improving sampling method (stratified) - Improving data collection procedure (take at one sitting, postpone and repeat fieldwork) Levels marked: Level Marks Descriptors 3 6-7 o Response demonstrates accurate knowledge of criteria for accurate data collection methods, both of the use of the infiltrometer and the sampling technique, and critically evaluates the described process issues for both accuracy and/or reliability. o Recommendations are given for addressing the issues. o Reflects a good understanding of the context of the investigation by citing relevant information from the resources and preamble 2 3-5 o Response demonstrates good knowledge of data collection methods. Provides an explanation of issues relating to reliability and/or accuracy with some reference to possible improvements. Description may be limited in depth and detail or apply mostly to only one set of measurements o Brief mention is made of recommendations to address the issues o Some reference is made to relevant information from the resources and preamble. 1 1-2 o Response shows superficial knowledge of relevant data collection methods. Some reference is made to issues with accuracy and reliability but may recommend inappropriate or irrelevant improvements or provide incorrect explanation of methods. o Response may be of limited relevance to the given context. Little or no reference is made to resources. (e) Discuss the value of this geographical investigation and its potential contribution to the management of urban runoff in Bukit Batok. [8] Indicative content: Value of the investigation is in validating the effectiveness of the raingarden as a SUDs (sustainable urban drainage system) strategy for managing pluvial flooding. Findings of the investigation can be used by PUB to refine and improve on their plans or to extend their plans to the rest of the canal. Evaluation of the limited scope of the findings and suggestions on further extensions of investigation (e.g. extending sample to different ground surfaces, investigation into canal discharge patterns, water testing for quality of raingarden effluents, longitudinal studies of infiltration rates) Levels marked: Level Marks Descriptors 3 7-8 Response demonstrates a clear knowledge and understanding of the context in the question. Uses relevant, detailed and accurate factual information and conceptual understanding. Reflects strong critical thinking skills and may include perceptive insights for the strongest responses. Source(s) is well used to support the response. o Provides a logical and well-developed evaluation well founded on evidence and/or different viewpoints.

3 2 4-6 A satisfactory response which is generally sound and contains relevant points, but may not always focus on the context in the question. Uses factual information and conceptual understanding that is generally appropriate to the given context but lacks detail and may contain some inaccuracies. Displays general critical thinking skills. Source(s) is used to support parts of the response. o Provides an evaluation, which may be limited in depth and sufficient elaboration in some parts. 1 1-3 Response shows a poor understanding of the context in the question. Uses basic factual information and conceptual understanding which has some, but limited relevance to the question. Source(s) is not used or not accurately used to support the response. o Provides little or no evaluation 0 0 No creditworthy response. Theme 1: Tropical Environments Tropical Climates 2 (a) Compare the global pattern of atmospheric pressure in December with that in June as shown in Resource 4. [3] Award 1m for each comparison point with citation of example • Latitudinal shifts in high pressure and low pressure centres between December and June - Inversion of high and low pressure - Persistence but latitudinal shift of subpolar pressure centres. • land-sea differences in shifts of pressure centres (b) With reference to Resource 5, explain the seasonal change in the earth’s radiation balance. [4] Award 2m for stating key seasonal changes to zones of radiative surplus and deficit, and citing evidence from Resource 5 Award 2m for explanations of changes: - Seasonal shift of subsolar point due to tilt of the earth’s axis in relation to plan of ecliptic. - Seasonal shift of Hadley cell and ITCZ providing cloud cover - Differences between hemispheres in terms of land-sea surface difference of albedo (c) Referring to Resources 4 and 5, discuss the extent to which atmospheric pressure may be attributed to solar heating. [7] Indicative content: - Solar heating affects atmospheric pressure through influence of the atmospheric temperature range and seasonality. Where the earth’s surface receives more intense and prolonged solar heating, temperature profiles are generally high, and this in tur