Simple Chemical Reaction: How to fill up a balloon

Here follow my instructions for the balloon experiment. Is it possible to fill up a balloon without inflating it yourself? What happens if you mix two substances with each other? How can you get a more powerful reaction?

Remember to start the experiment with a hypothesis, what do you think will happen?

Instructions for parents: Read this first.

Material included:

  • Two plastic bottles
  • Baking soda
  • Water
  • Vinegar
  • Two balloons

Additional things you will need:

  • Spoon
  • A piece of paper or a funnel


  1. Discuss your hypothesis.
  2. Pour the baking soda into the balloon. Use a funnel or roll a piece of paper as a funnel to make it easier to get the baking soda in the balloon.
  3. Fill one plastic bottle with one third with water.
  4. Put the balloon on the top of the bottle, and mix the baking soda with water.
  5. What just happened?
  6. Now try to do steps 2-4 but with vinegar instead of water.
  7. Was there a different reaction?
  8. Try to vary the amount of water, vinegar, and baking soda.


When baking soda is mixed with water and/or vinegar, the gas forms carbon hydroxide. A simple chemical reaction occurs and it starts bubbling. The gas takes much more space than liquid, which increases the pressure in the plastic bottle. The pressure blows up the balloon. To get an even more powerful reaction, water is replaced with vinegar.


Both baking soda and vinegar are harmless, but you should avoid getting any of it in your eyes.


To see others do the experiment look at this video:

Do you have any questions or comments about the experiment? Just leave a comment below!

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