Annex A - Group Research Proposal

Below is our final group proposal. For a clearer and more organised version, you may wish to visit this link.

School of Science and Technology, Singapore
Science Research Project (Investigative Skills in Science)
Done by:  Quek Gene Yong, Klaudia Oey, Melodee Chia, Sammi Lim
Class of S2-04’15
Group C

Purpose of this research
The purpose of this research is to test a hypothesis, in other words, this research is hypothesis-driven. Hence, we are investigating the effects of antibacterial cleaning agents on bacteria.

A.  Question being addressed

B. Hypothesis Equipment List  &  Procedures

C.    Equipment List  &  Procedures

D.   Safety Precautions & Result Analysis

E. Bibliography

A. Question being addressed

The question we ultimately want to answer would be
“Which antibacterial agent is the best in killing bacteria?”
(i) The reason for conducting this experiment
The reason this experiment is conducted is because we want to prove the abilities of cleaning agents. Many cleaning agents on the market claim to have superior cleaning quality that can clean and remove almost all bacteria on surfaces, and we want to know if that is true.
(ii) Variables
Independent Variables : Brand of antibacterial agent used          
Dependent Variables : The percentage of bacteria killed
Constant Variables: The volume of antibacterial agent used, type of Agar, volume of agar, type of broth, amount of bacteria in each petri dish, type of petri dish, environment petri dish is left in (such as the surrounding temperature, amount of moisture,etc.)

B. Hypothesis
           If Dettol is used, it can kill more bacteria than the rest of the agents.
In other words, we believe Dettol is the best product out of  the few antibacterial agents we have chosen for this experiment.

    (i) Justifications and Reasoning
Dettol has been around for 80 years, and its strong history and long-lasting branding and consumer feedback is a reason why we choose Dettol as the best antibacterial product in the market. When soaps or cleaning agents are mentioned, many people commonly mention Dettol first.
(“Over 80 years”, n.d.)

Also, as advertised on advertisements, it is said to be scientifically proven that Dettol can remove up to 99.9% of germs and bacteria. One of Dettol’s advertisements can be found here:
(T Entertainment, 2013)

In this article, it is shown in the charts that Dettol is ranked 3rd Position for the most trusted brand in India.
(“Trust is a scarce and fragile resource in the world of marketing”, 2014)

(“Our brands.”, n.d)

(“Grocery News”, n.d.)

From the above article, Dettol is said to be proven to combat germs, and kill germs such as Methicillin-resistant Staphylococcus aureus, Flu Virus, Escherichia coli and Salmonella.
We would like our experiment to compare the more popular and well-known brands of possessing antibacterial effects. Thus, the rationale behind the choosing of the brands is that we want to make sure there is a certain reputation for these brands and conduct our experiment to show which agent actually lives up to their advertising and their branding.
Other Brands that we are going to use

Lifebuoy: As advertised, LifeBuoy is said to be scientifically proven to kill 99.9% of germs in 10 seconds.  
(“Lifebuoy”, n.d.)

Mama Lemon: Mama Lemon has also been proven to be Singapore’s No. 1 Selling Dishwashing Liquid. It’s webpage also advertises that it can get rid of 99.9% of bacteria. 
(“Mamalemon”, n.d)

Clorox Bleach: As advertised on the webpage, Clorox is proven to remove 99.9% of germs.

(“All Purpose Cleaner”, n.d.)

Amount of bacteria
Number of Colonies
Amount of bacteria sample spread
100 µL
Amount of cleaning agent spread
10 µL

Materials Needed:
Petri Dishes with LB Agar
25 Dishes
L Shaped Glass Rods
10 Packs
Inoculation Loops
10 Packs
Pipette (100µL+1000µL)
2 Pipettes
Pipette Tips (100µL+1000µL)
1 Box/Pipette
Centrifuge Tubes, Plastic
1 Pack 
Distilled Water
2 x 500mL
E. coli & B. subtilis Samples

D: Procedures

Preparing the bacteria for experiment

  1. Prepare 10 agar filled petri dishes, and label them 1-10 
  2. Prepare 10 centrifuge tubes of 9mL distilled water each, and label them 1-10
  3. From the sample of E.coli, using the 1mL pipette, transfer 1mL of the sample into the distilled water in tube 1, and cap the tube and invert tube to make sure bacteria is mixed evenly
  4. From the sample in tube 1, take out 1mL of the mixture into 9mL of distilled water in tube 2, cap the tube and invert tube to make sure bacteria is mixed evenly
  5. Repeat step 4 with different tubes until all 10 tubes are filled
  6. Pipette 0.1mL of the mixture from centrifuge tubes 1-10 into petri dish 1-10 respectfully, and spread evenly with the L shaped glass rod
  7. Incubate the 10 petri dishes overnight at 37 degrees Celcius
  8. After the incubation, check each petri dish for the number of colonies. Use the petri dish that has 30 - 300 colonies.
  9. Check the petri dish number of the dish that is chosen, and use the corresponding dilution for future incubation (in experiment)
* In any case that 10 dilutions still produce too much bacteria, continue to dilute further.

Conducting the actual experiment
  1. Label 4 agar filled petri dishes according to the antibacterial agent to be spread on it and leave one as a control
  2. Using the tube that was chosen previously, spread 0.1mL into each petri dish
  3. Using the L shaped glass rod, spread the bacteria evenly across the petri dish
  4. Pipette 0.01mL of each anti-bacterial agent onto its respective petri dish
  5. Using the L shaped glass rod, spread the anti-bacterial agent evenly across the petri dish
  6. Incubate all the dishes overnight at 37 Degrees Celcius overnight
  7. Repeat steps 1-6 two more times.
  8. Gather results in the results below
*In any case that the agent used is too thick, using a pair of flamed scissors, cut the tip before pipetting the agent.

Trial number / Amount of bacteria
Number of bacterial colonies in “Dettol” petri dish
Number of bacterial colonies in “Mama Lemon” petri dish
Number of bacterial colonies in “Lifebuoy” petri dish
Number of bacterial colonies in “Clorox” petri dish
Number of bacterial colonies in
control  petri dish
Trial 1

Trial 2

Trial 3


After recording data collected in the table above,  we would plot a bar graph above based on the percentage of colonies in the dishes against the control.


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

  1. Be careful not to burn ourselves when handling items near the open flame.
  2. We should wear gloves when handling the petri dishes so as to not get any infections etc. 
  3. When handling the antibacterial agents(eg. Bleach), use gloves to prevent skin discomfort. 
  4. Avoid leaving the flame unattended

Data Analysis: Describe the procedures you will use to analyze the data/results that answer research questions or hypothesis

We would first have to observe how many colonies of E.coli  there are in the different petri dishes after a few days. Then, we will record the results into the table as shown below.

  1. Compare all the values written on the table
  2. Using the number of colonies in each petri dish of antibacterial agent, express it as a percentage of the number of colonies in the control petri dish.
  3. Using the number of colonies found in each petri dish, plot two bar graphs (Number of colonies and percentage of colonies) to analyse the data. The lowest “bar” is the most efficient antibacterial agent out of all the agents chosen.


  1. Our History. (n.d.). Retrieved from
  2. T Entertainment. (2013, January 6). Dettol Singapore TVC 2012 (Chinese Version) [Video file]. Retrieved from
  3. Trust is a scarce and fragile resource in the world of marketing (2014). Retrieved from 
  4. Our brands. (n.d) para 4. Retrieved from
  5. Grocery News from the Grocery Trader Magazine including all Grocer news today. (n.d.) para 1-4. Retrieved from
  6. “Sanitizer”. (n.d.). Retrieved, from
  7. Mamalemon. (n.d.). Retrieved, from 
  8. Clorox® Clean-Up® Cleaner Bleach. (n.d.). Retrieved  from


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