Carbon Dioxide Balloon Race STEM Challenge

Have you ever mixed vinegar and baking soda (and maybe a little red food coloring) to create a homemade volcano?  It’s fun to see the reaction of these two common household chemicals.  But what is happening at the molecular level that makes these two substances react? 

This reaction is known as an acid-base reaction.  Vinegar is the acid and baking soda is the base.  Acids have a hydrogen ion, and bases have a hydroxide ion, which is one oxygen and one hydrogen bonded together. 

When the acid and base come together, the base’s hydroxide ion takes the acid’s hydrogen ion.  So, then you’ve got TWO hydrogens and ONE oxygen….H2O!  You’ve made water! 

The other chemicals in the acid and base will bond together to create salt.  In the reaction between baking soda and vinegar, the bubbles are caused by molecules of carbon dioxide, or CO2, that are released from the baking soda. 

The question you’re exploring today is: How does temperature affect the rate of this reaction?  Do you think the reaction will be faster or slower at warmer temperatures?

Carbon Dioxide Balloon Race STEM Challenge

How to do the Carbon Dioxide Balloon Race STEM Challenge

The Challenge: Find out how temperature affects how quickly a balloon fills with carbon dioxide from a baking soda and vinegar reaction.

Materials: two (or more) empty plastic bottles of the same size, vinegar, baking soda, a funnel, and two (or more) balloons

Challenge Criteria: In each bottle, pour ½ cup of vinegar.  Use the funnel to put 3 teaspoons of baking soda into each balloon.  Put ½ cup of water in two different cups, then find a way to bring them to different temperatures (one cold, one hot).  Then, pour the water into the water bottles with the vinegar.  Place the opening of each balloon over the mouth of the bottles, without dumping any of the baking soda into the solution yet.  Then, lift the balloons so that the baking soda falls into the vinegar solution at the same time.  Watch what happens!


Which balloon blew up faster?  Which one got bigger?  How does temperature affect the speed of the reaction? 

Challenge Extension

Try using water with even more extreme temperatures (have an adult help you heat the water safely) to see what happens!

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