Here’s one just for fun because we love chemistry! Today, let’s inflate a balloon using only baking soda and vinegar. This is a perfect indoor activity during these cold winter months.

We’ve done several activities using baking soda or Alka Seltzer and vinegar because they’re household items that everyone has on hand, and you can do so many different types of reactions with them! From volcanoes to lava lamps to rockets and inflating balloons, the possibilities are endless.

So, what materials do you need? Easy. A balloon, an empty plastic soda or water bottle, a small funnel, baking soda and vinegar.

Here are the steps to inflate your balloon:

  1. Using the funnel, add 2 tablespoons of baking soda to the balloon.
  2. Pour 4 ounces (1/2 cup) of vinegar into the bottle.
  3. Carefully, fit the balloon over the bottle opening. You don’t want the baking soda to fall into the bottle of vinegar yet.
  4. Once the balloon is fitted tightly on the bottle, hold up the balloon and let the baking soda fall into the bottle of vinegar.
  5. Observe the reaction, and feel the bottle temperature while it is occurring.
  6. Ta-da!

Can you explain how this worked?

The reaction of baking soda (sodium bicarbonate) and vinegar (acetic acid) produces carbon dioxide gas, water and sodium acetate. When you first mix baking soda and vinegar, you’ll see bubbles in the solution. This is the carbon dioxide, which is then released from the liquid. There is not enough space in the bottle for the carbon dioxide gas, so it moves into the balloon, inflating it. There is also an endothermic reaction, which is what causes the decrease in temperature that you may have felt during the reaction.

The amount of baking soda and vinegar you use will only produce so much carbon dioxide gas. Therefore, at a certain point, depending on how much you use, the balloon will stop inflating. To further this experiment, try doubling the amount of vinegar and baking soda. Will the balloon get twice as big? What happens if you change the ratio of baking soda and vinegar?

Try having a contest to see who can get their balloon the biggest. What combination of vinegar and baking soda produced the largest balloon?