'Biochemical Oxygen Demand' (BOD) Experiment is a SUCCESS!

- On the 6th day after we conducted the experiment, FINALLY, one of the water sample shows the result.  YAYYY!

Water sample of Sungai Rait turns from blue to colourless

- This means, Sungai Rait has the most polluted water among other rivers.

The top view of Sungai Rait's water sample

- As of other water samples, there have no sign of change in colours.

Here, take a look.

Distilled Water

Sungai Lutong

Sungai Baong

Sungai Lusut

Sungai Bakam

- All water samples are still in the colour of Methylene Blue solution (Blue)

So, stay tuned for our next post & the results of the other water samples too! 

(PBL) Project Based Learning: Doing The 'Biochemical Oxygen Demand' (BOD) Experiment

(Preparing the Apparatus & Materials) 

Getting a 0.8 ml of Methylene Blue solution using a syringe.

Pouring the water sample of rivers in the beakers.

(Starting the experiment)

The bad odour from the water sample from different rivers

Pouring water samples into the beakers.

All 5 water samples + 1 Distilled water (act as a controlled)  and 6 beakers for one each.

Distilled water - Act as a controlled

- Releasing the 0.8 ml of Methylene Blue solution into the water sample

Slowly releasing the Methylene Blue solution

Completely released all 0.8 ml of Methylene Blue solution  in to the water sample

Stir the solution gently

Continue releasing Methylene Blue solution on other water samples

(Time recorded)

Record the time until the solution fully decolourise.

Patiently waiting... *tick tock tick tock*

Finally, all water samples are filled with 0.8 ml of Methylene Blue solution

- These solution are then kept in a box to prevent from direct sunlight.

WHY?

- It is to prevent the microorganism inside the water sample to carry out photosynthesis. Through photosynthesis, the organisms will release oxygen thus decrease the rate of decolourising of the solution.