Paper3: BOD Level

Example of report writing

Problem statement :

What is the level of water pollution in different sources of river water?

Aim of investigation :

To determine the level of water pollution in different sources of river water

Variables :

Manipulated:     the sample of water from different rivers

Responding:      time taken for methylene blue to decolourise

Control:             volume of water sample //volume of methylene blue//concentration of methylene

                          blue

Statement of hypothesis:

The time taken for the methylene blue solution to decolourise with the water from river A is faster than with the water from river B.

List of apparatus

(250ml) reagent bottle with stopper, beaker, syringe, stopwatch

List of materials

Water sample(at least 4 type), methylene blue solution(0.1%)

Technique used

Record the time taken for methylene blue to decolourise by using  a stopwatch.

Experimental procedure

 

1. Water samples are collected from four  different rivers.      ( Distilled water is used as a control). (K1 +K4)
2. Four reagent bottles are labelled as A,B,C, D and E. (K1)
3. Each reagent bottle is filled with the following water sample. (K4) (at least four water samples)

A-water from river 1 (or place A etc)

B-water from river 2

C-water from river 3

D-water from river 4

E- distilled water

4. 1ml of methylene blue solution is added (K2) by using a syringe (K1) to the base of each water sample (K5) in each reagen bottle. (K1)
5. Each reagent bottle is then closed quickly with a stopper (K1).
6. The reagent bottle cannot be shaken. (K5)
7. Each reagent bottle is kept in a dark place(cupboard) (K1) and then the stopwatch is started. (K3)
8. The bottles are examined from time to time. (K1)
9. The time taken for methylene blue to decolourise is recorded (in a table for all water sample) (K3)

Presentation of data

Data is presented in a table with correct title & unit

Source of water	Time taken to decolourise methylene blue solution (minutes or hours)	Level of water pollution
A
B
C
D
E

Conclusion :

The time taken for the methylene blue solution to decolourise with the water from river A is faster than with the water from river B.