Michelle McKey’s fourth grade science class at Escambia County Middle School performed an experiment using a two-liter bottle, baking soda, apple cider vinegar, and a balloon. The experiment showed how mixing the baking soda and apple cider vinegar makes a mixture of gas called carbon dioxide (CO2). It caused the balloon to blow up because of the air that formed in the two-liter bottle. The students observed the experiment and made notes in their science notebook.