Carbonation Used to Blow Up a Balloon as a Science Project

Method

• One way to test the amount of carbon dioxide in a beverage is to drill a hole in the bottle cap and cover it with an uninflated balloon. As the trapped carbon dioxides leaves the soda, the balloon will gradually fill with all of the carbon dioxide contained in the beverage. By using the same type of balloon for each study, you can measure the diameter of the balloons to gauge the volume of carbon dioxide in each bottle. In addition to testing different soft drinks, you can also test the difference between an old and a new carbonated beverage to track the rate of carbonation loss over time.

How It Works

• During the carbonation process, carbon dioxide is dissolved in aqueous solutions such as soda and water. When you drill a hole in the cap, or unscrew the lid for the first time, the carbon dioxide leaves the bottle as a gas in a process called effervescence. Since carbon dioxide is lighter than air, it rises out of the bottle and fills the balloon, converting from H2CO3 to H2O + CO2.

Planning Your Science Projects

• To start, you will need to create a hypothesis that illustrates what you think will happen during the experiment. For example, if you think that older carbonated beverages will contain less carbon dioxide than newer ones, that would be your hypothesis. Other potential hypotheses include comparisons of brand, type of beverage, temperature and storing methods. Develop an identical procedure for testing each bottle, and measure the diameter and length of each balloon to determine the volume of carbon dioxide contained in each bottle.

Alternatives

• The Science Kids website recommends this alternative to testing pre-packed carbonated beverages. Begin with an empty soft drink bottle, and pour 40 milliliters of water into it. Add a teaspoon of baking soda, and shake the bottle thoroughly until it has dissolved. Finally, pour lemon juice into the bottle, and quickly cover the mouth with an uninflated balloon. The way this experiment works is by creating carbon dioxide from a chemical reaction between the baking soda and lemon juice. Try out different variations to determine which reaction creates the biggest balloon.