2. Methods


Equipment list: 

-Incubation chamber x 1
-Cotton swab with nutrient broth x 6
-L Spreader x 18
-Gloves x 4 pairs
-Para flims x 18
-Agar Plate x 18
-Micropipete x 2
-Micro fuge tube x6



Locations where we collect our samples.
-Staircase Railing
-Toilet Bowl
-Canteen Table
-Classroom Table
-Classroom Door Handle
-Locker




• Procedures: Detail all procedures and experimental design to be used for data collection
Procedure 1: Obtaining the samples
  1. Use the Quick Swab and swab each of the locations. (Staircase Railing, Toilet Bowl, Canteen Table, Classroom Door Handle, Locker).
  2. Make sure the duration of swabbing is equal and that all sides of the cotton bud must have bacteria. So, swab it in all directions. 

Procedure 2: Dipping the cotton bud in nutrient broth
  1. After swabbing, break the top of the quick swab to release the nutrient broth until you hear a “Pop” sound.    


2. Squeeze the top such that all the nutrient broth is released
3. Wait for 30 seconds until all the bacteria has been transferred from the swab to the nutrient broth.





Procedure 3: Transferring the nutrient broth to the microfluge tube and using the micropipette to extract it.
  1. After the bacteria has been transferred from the swab to the nutrient broth, pour all the nutrient broth gently into the microfluge tube. (Make sure there are no spillages as this could case a “germ invasion”.)
  2. Use the micropipette and put the micropipette tip on.(Make sure that the extraction level is 100 ul)





2. Press the top of the micropipette gently (2/3) and place it 2/3 in the microfluge tube.


3. Extract 100 ul from the microfluge with the micropipette.


Procedure 4: Placing the nutrient broth on the agar plate

1. After extracting 100ul of the nutrient broth from the microfuge tube, gently release the nutrient broth from the micro-pipette onto the agar plate.


2.  Then, use the L spreader to spread the nutrient broth on the agar plate evenly.



Procedure 5: Sealing the Agar Plate
 1.  Then, seal the agar plate using parafilm. (Make sure to stretch the parafilm around the agar plate.)



2. Ensure that the parafilm is tight by flipping the agar plate and testing it, and if it is not secure or if it snaps, remove the parafilm and place another one around the agar plate.


Procedure 6: Incubation
  1. Stack the Sealed Agar plates on top of each other and place them into the incubation chamber.

2. Set the temperature to 37 degrees celcius and wait for 18 hours before checking back on them.


Procedure 7: Observation and Conclusion
  1. Take out the bacteria samples from the incubation chamber.
  2. Compare the different colors of bacteria, identify which is the most common bacteria and which has the most amount of bacteria.



• Risk and Safety: Identify any potential risks and safety precautions to be taken.


1)We may get Infected by the bacteria that we come across

Description : We might get diseases that cause symptoms such as cough, flu and fever and in severe cases, death. The bacteria we are trying to experiment is harmful to us. Thus, we can get infected by the bacteria if we are not careful.
Precaution taken : Wear gloves , lab coats and goggles when handling bacteria. 

2)We may not handle the solution (nutrient broth) correctly.
Description : Nutrient Broth helps bacteria to grow. If nutrient broth is spilled, we may cause a “germ invasion” (Students may get sickness, diseases) in school.
Precaution taken : Handle solutions with care. Wear gloves in case the solution spilled on your hand. Clean up the solution quickly once it is spilled.

3) We might drop the petri dishes, and if someone comes into contact with the dropped petri dish, he/ she may get infected .
Description: If we drop the petri dishes, the bacteria samples may stick to the floor and grow on it. This may cause a disease outbreak.
Precaution: Do not drop the petri dishes and do not handle it if you are clumsy.

4) We might swab the different areas at different timings.
Description: The results might differ if the timings are different, making the experiment not fair.
Precaution: Use stopwatches or your phone to record the timing taken.

5) The encased nutrient broth in the cotton swab may leak.
Description: As the nutrient broth is stored in the container on the top of the cotton swab, the nutrient broth may leak, making the experiment unfair as the bacteria will multiply even before the experiment begun. 


Precaution: Make sure the Nutrient broth is not leaking before doing the experiment.

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