Hooked on Science: Carbon dioxide seesaw

Materials

• Balance
• Two brown paper bags
• Vinegar
• Baking soda
• Pitcher

Instructions

STEP 1: Attach a brown paper bag to each side of the balance.

STEP 2: In the pitcher, mix two cups of vinegar with one cup of baking soda. Feel the side of the pitcher. Is the side of the picture hot or cold?

STEP 3: Quickly pour the newly formed gas into one of the brown paper bags and observe. Pour only the gas and not the liquid.

Explanation

Although we can't see it, carbon dioxide gas is produced as a result of a chemical reaction between the vinegar and baking soda. As you pour the gas into one of the bags, the balance shifts, proving the carbon dioxide gas is present. The gas is matter, which is anything that has mass and takes up space. The side of the pitcher gets cooler when the vinegar and baking soda are mixed. This kind of change is an endothermic reaction, which is a change that takes in heat.

Jason Lindsey is a science outreach educator with Hooked on Science. Check out his website, hookedonscience.org, for webcasts and experiments.