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