Research Proposal

S202 Group D 
Research proposal 
Research title:
An investigation on the pH solution and its effect on tooth decay.
A. Question or problem being addressed 
- To find out if the pH value of beverages affects the level of decay (corrosion) on our teeth.

Independent Variable: 
- The pH of the solution

Dependent Variable: 
- The change in mass of the eggshell indicating the level of corrosion. 

Constant Variables: 
1. The type of eggs.
2. The temperature of the surroundings.
3. The amount of pH solution put into each beaker.
4. The type and size of the beaker.

B. Hypothesis

The lower the pH value (more acidic), the greater the level of decay.

C. Description in detail of method or procedures

Equipment list:
1. Beaker x10
2. Different pH solutions ( 3,4,5,6 )
3. Eggs x20 ( 4 for control ) 
4. Paper towels
5. pH sensor
6. Electronic balance 
7. Water (to act as a control)

*Note that the eggshells should be  white to better resemble the colour of our teeth.


pH solution 
  1. Mix the pH solution 
  2. Use a pH sensor to test the pH of the solution to make sure it is the correct pH that we require ( 3,4,5,6)

Soaking the eggshells in the pH solutions:
1. Crack and empty out the contents of 20 eggs. Use 4 eggs for the control
2. Rinse the eggs thoroughly.
  1. Dry the eggshell with a paper towel.
  2. Put the eggshell on a bowl and weigh the eggshell using the electronic balance and record the data on the logbook. Then, find out the mass of the bowl and minus it off to find out the mass of the eggshell. ( Do this before and after each experiment. )
6. Fill other beakers with 200ml each of the different pH solutions.
  1. Soak two eggshells in each pH (3,4,5,6) solution.
8. Put the beakers side by side under room temperature for 5 days
  1. After 5 days, remove the eggshell, one at a time from the solution and dry it.
  2. Weigh the eggshell using the electronic balance and record down the results on a logbook.

Risk and Safety:

1. Do not spill solutions as they are acidic. 
2. Food and pH solutions in the experiment are not meant for consumption.
  1. Be careful with the beakers as they are brittle.

Data collection: 

1. Measure the pH value in each solution and make adjustments until it matches the pH value of 3, 4, 5 and 6.
2. Weigh each eggshell on the electronic balance before soaking the eggshell in the solution. 
3. Weigh each eggshell after 1 week and record down the difference in mass. ( Find the average of the eggshells 
4. Set up a table with the different pH value solution as heading 
5. Fill in the weight of the eggshell in week 1 before and after 1 week (5 days) below the heading
6. Fill in the weight of the eggshell in another column in week 2 before and after week 2.

Data analysis:

  1. Calculate the difference in the weight of the eggshell before and after it was soaked in the solution.
  2. Take the average of the two eggs in the same pH solution 
  3. Compare the differences of the average of the eggs in the different pH solutions
  4. The greater the average weight difference before one week and after 5 days indicates the higher the level of corrosion.
  5. Relate the pH value beverage to the weight difference of the eggshell.
  6. Conclude if our hypothesis is correct based on the findings.
Electronic balance:

  1. Take the eggshell, dry it and put it on the electronic balance
  2. Wait for the measurement on the electronic balance to stop changing 
  3. Record down the results on the logbook
  4. Repeat steps 1-4 after each test


-Alfred,D. ( 2013, July 16 ) What causes tooth enamel damage? Retrieved from:

- Bozart,A. ( 2013 , July 16 ) 7 Foods that Stain your Teeth the Most. Retrieved from: .

- Braun,C. ( 2013, July 13 ) Science Projects on Soda & Teeth. Retrieved from:

- Freeman,D. ( 2013, July 16 ) Foods and habits that stain your teeth. Retrieved from:

- Friz,A. ( 2013, July 16 ) 12 foods that stain teeth. Retrieved from:

- Gardner,A. ( 2013, July 16 ) Best and worst foods for your health. Retrieved from:

- Pico technology (2013 , July 20) Testing the pH Level of Common Drinks Using DrDAQ as a pH Meter . Retrieved from

1 comment:

  1. Please finalised your research proposal by Wed the latest! If you need help please seek consultation with me asap.