Sixth graders can conduct a science experiment to create a self-inflating balloon by mixing an acid and a base to create a chemical reaction. Baking soda and vinegar, when combined, produce carbon dioxide that can be trapped inside a balloon.
Education.com recommends using a balloon, a bottle, a funnel, 2 tablespoons of baking soda and 4 ounces of vinegar to conduct this experiment. Use the funnel to put the baking soda inside the balloon and pour the vinegar into the bottle. Secure the opening of the balloon firmly around the top of the bottle and allow the baking soda in the balloon to fall into the vinegar. The base (baking soda) and acid (vinegar) react and form carbonic acid which decomposes into water and carbon dioxide. The carbon dioxide expands and fills the balloon.
Higher quantities of acid and base can be combined to produce more carbon dioxide and a bigger balloon. Lemon juice can be substituted for vinegar. A test tube or beaker can be used instead of a bottle. Other variables that can be manipulated in the experiment include the percentage of acetic acid and water in the vinegar, the temperature of the vinegar and whether the baking soda is added to the vinegar or vice versa.