Simple Science: Chemical Reaction in a Bag - MetroFamily Magazine
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Simple Science: Chemical Reaction in a Bag

by Steve Davala

Reading Time: 2 minutes 

Need a science activity for your child that won’t require you to go out and buy a bunch of supplies? The following experiment is a lot of fun, but will also teach your kids a little bit about chemical reactions. More importantly, it will instill in them the scientific inquiry mindset that is needed in schools today.


To see what happens when you mix vinegar and baking soda in a sealed bag


  • film canister (or similar container)
  • Quart size Ziploc bag that seals
  • ¼ cup vinegar
  • 1 teaspoon baking soda
  • thermometer


  1. Put one teaspoon of baking soda in the film canister
  2. Pour ¼ cup of vinegar into the Ziploc bag
  3. Find and record the temperature of the vinegar
  4. Stand the baking soda cup in the bag but DON’T mix it yet
  5. Zip the bag shut and squeeze the air out
  6. Predict what will happen to the bag and the temperature when you mix the baking soda into the vinegar
  7. Mix ALL the baking soda into the vinegar by turning the bag over
  8. Make and record observations!
  9. Open the bag and measure the temperature of the liquid
  10. Ask what can be done differently and repeat the experiment
  11. Prompt further thinking with questions like “How does more or less baking soda or vinegar affect the temperature or how quickly the bag fills up?”  and “How does the temperature of the vinegar affect things?”

The Science Behind the Experiment

The chemical reaction between vinegar and baking soda creates carbon dioxide, a gas. Since gasses take up more space than the liquid and solid combined, the bag inflates. The weight of the bag does not change throughout the experiment since nothing new is created, the old just changes form. The temperature drops because the reaction is “endothermic,” meaning it keeps pulling in heat to react.


Science is about making discoveries about the world around us. It’s about asking good questions and knowing how to get them answered. By providing opportunities like the one above and knowing how to ask questions that will get your children to think, you’re helping them develop scientific minds, ready to solve any problem put before them.

Steve Davala is a local middle school science teacher who likes to write. He’s got two kids of his own and subjects them to these science activities as guinea pigs. 

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