Baking soda and water are easy to find around the house or at the grocery store and give you a great variety of science experiment options. Baking soda is a base, so it will form a chemical reaction when combined with an acid such as vinegar or orange juice. This chemical reaction produces carbon dioxide, which causes bubbles to form. So chose your favorite science fair experiment using baking soda and water and observe the reaction for yourself.
The Exploding Lunchbag
To conduct the Exploding Lunchbag experiment, go outside or somewhere where you can make a mess. Fill a plastic sandwich bag with 1/4 cup warm water and 1/2 cup vinegar. Put 3 teaspoons of baking soda in the middle of a tissue and fold it to form a little packet. Quickly slip the baking soda packet into the bag and close it. Step back and watch the explosion. Conduct the experiment again but vary one element, such as the size of the bag, to answer a question such as, "Which size bag creates the biggest pop?" or "How long do different bag sizes take to pop?"
To make your spaghetti swim, fill a clear glass or bowl with one cup of water and two teaspoons of baking soda. Mix them together. Break spaghetti into 1 inch pieces and drop it into the water and baking soda solution. Pour in 5 teaspoons of vinegar and observe how the spaghetti reacts. Perform the experiment again using only water and vinegar to answer the question, "What is the effect of baking soda combined with vinegar on spaghetti?"
To make invisible ink, combine 1 tablespoon water with 1 tablespoon baking soda. Mix it together, then use a toothpick dipped in the solution to write a message. Let it dry, then paint over the message with a paintbrush dipped in grape juice concentrate. The acid in the grape juice will react with the base in the baking soda and reveal the message. Perform the same experiment, but paint the message with only water to answer the question, "What is the effect of acidic grape concentrate on baking soda compared to water?"
Salt vs. Baking Soda Dissolving
Fill two test tubes with water. Add 2 tablespoons salt to one test tube and 2 tablespoons baking soda to the other. Mix both solutions thoroughly, then wait two hours. Compare the test tubes to see which element dissolves better to answer the question, "What dissolves better in water, baking soda or salt?"