This is the second experiment we did in the 0-5 section of the Lied Discovery Children’s Museum in Las Vegas. The kids got a water bottle with maybe half a cup of white vinegar in it, topped with a balloon with about one tablespoon of baking soda. In this picture the lady running the experiment is explaining to them that the balloon is going to inflate. That sideways look on Emma’s face means she doesn’t buy it.
Turns out the lady was right; the combination of baking soda and vinegar creates carbon dioxide, which inflates the balloon. Emma was duly impressed =)
If you try this at home, you may need to hold the balloon in place (Mike is doing this in the lower photo) to keep it from flying off the top of the bottle as it inflates. Once inflated, it stays put pretty well =)