Kitchen Science Lab for Kids: 52 Family Friendly Experiments from Around the House (Hands-On Family) by Liz Lee Heinecke

Watch a bubbly chemical reaction inflate a balloon with invisible carbon dioxide gas.

The scientific name for baking soda is sodium bicarbonate. Kitchen vinegar is diluted acetic acid. When mixed together, these two chemicals react to form some new chemicals, including carbon dioxide gas, which inflates the balloon. We know a reaction is happening because we can see bubbles forming, the bottle feels cold, and the balloon inflates with the invisible gas.

Step 1: Pour 1/3 cup vinegar into the soda bottle. Step 2: Hold the mouth of the balloon open and use a spoon to pour 3 tsp. or so of baking soda into the balloon. This takes two people, one to hold the balloon open and one to add the soda. Step 3: Shake the soda down into the “bulb” or the main part of the balloon. Carefully stretch the mouth of the balloon completely over the mouth of the bottle, keeping the main part of the balloon off to one side, so the baking soda isn’t dumped into the bottle until you’re ready. Step 4: Holding the mouth of the balloon on the bottle, shake the soda into the bottle, all at once.