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GC BIOLOGY SMK BUNUT SUSU, PASIR MAS.

12 June 2010

form 5 P3 Q2

Correction

Biology PKBS 2

Form 5 - Paper 3 Qn 2 (BOD).

#{ 1 time= 1 BI, 5 times = 3 BI + 2 BM , 8 times = 5 BI + 3 BM, 10 times = 6 BI + 4 BM }#

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Sample answer:

1. Problem

Statement: What is the effect of different distance between the rubber factory

and the village on the rate of water pollution?

2. Aim : To investigate the effect of the distance between the rubber factory

and the villages on the rate of water pollution.

3.Hypothesis: The longer the distance between the rubber factory and the

villanges , the lower the rate of water pollution.

4. Variables:

Manipulated V: The distance between the rubber factory and the villages.

Responding V: The rate of water pollution // The time taken for the methylene

blue solution to decolourised.

Control V: The volume of the methylene blue solution

5. Apparatus

& Materials : water samples, methylene blue solution, reagent bottle,

stop-watch, syringe, cupboard

6Technique : Record the time taken for the methylene blue solution to turn colourless

7. PRocedure:

  1. Water samples are taken from the river at villages P, Q and R
  2. 200ml of water sample from village P is transfered into the reagent bottle P.
  3. Using a syringe, 1ml of 1% methylene blue solution is slowly injected

into the water sample P.

  1. The tip of the syringe is used to stir the solution slowly.
  2. The bottle is capped immediately and placed in a cupboard.
  3. The stop watch is started.
  4. The reagent bottle is observed every one hour to determine whether the

methylene blue has been decolourised.

  1. The time taken for the methylene blue to decolourised is taken and recorded down.
  2. Steps 2 to 8 are repeated with the sample water from villages Q and R.
  3. The results are recorded in a table.

Result:

Water sample.

Time taken for methylene blue solution to turn colourless (min)

The rate of water pollution 1/t

(min-1)

P



Q



R



Consclution : The longer the distance between the rubber factory and the villanges

, the lower the rate of water pollution. The hypothesis is accepted.