1. Does pH Go with the Fizz?



    Investigate how the acidity of carbonated beverages changes over time.

    Research question

    How does the acidity of carbonated beverages change as the gas (CO2) exits the beverage?


    • Bottle or can of your favorite carbonated drink.
    • Beaker with at least 100 ml capacity.
    • Digital pH sensor, laboratory pH-meter, pH strips or other indicator of acidity.

    Why use data from multiple participants?

    The more researchers are involved in the project, the more varieties of drinks we can explore.

    Investigation Protocol

    1. Open the bottle or can and pour the water into a prepared clean beaker.
    2. Measure the acidity of the water. Measurements can be taken using a digital pH sensor, a laboratory pH-meter, litmus paper (strips) or other indicators of acidity.
      • If you are using a digital sensor or laboratory pH-meter, it is desirable to pre-calibrate them (see the Project Getting on the Same Page)
      • Repeat the test three times, each time washing the sensor thoroughly first, then wiping it dry. Enter all three measurements in the final report. The program will automatically calculate the average value, summing these three values of acidity and dividing the total by 3. The resulting value will be considered the average acidity. (You will see the results when you send the reports. These can also can be viewed in the “Findings” section in your profile after it is sent.)
      • If you use a litmus test measurement of acidity, follow the directions of the manufacturer,  A measurement using a litmus test, as in the case of sensors, should be repeated three times and all three values entered to make a profile.
      • After measuring, leave the soda container open.
    3. An hour later, if possible, or at the end of the lesson, repeat the measurement according to the method described in Sec. 2 of this Protocol. 
      After these measurements, continue to leave the bottle open.
    4. The third measurement should be taken the next day after a bottle or can has been opened. The measurement procedure is the same.
    5. For each measurement, fill in the Report Form, indicating when the measurement was made.
      If you decide to test several different brands of soda, then enter the results of each study in a separate Report Form.
    6. Follow the progress of the project, and participate in the discussion of the results obtained by other contributors.

    Safety tips

    Observe safety precautions when working with the pH meter as described in the user manual.

    Report Form Before filling in the Report Form, please read the Investigation Protocol