Fizzy cubes

Make a self-inflating balloon and experiment to find out which household liquids react with bicarbonate of soda.

a young girl with curly red hair has her hands up in delighted surprise as she looks at a balloon self-inflating
Viola is amazed at the balloon inflating itself, Image credit: The Royal Institution


Make a self-inflating balloon.

ExpeRiment to find out which household liquids react with bicarbonate of soda.

Learn how carbon dioxide gas is produced when we mix liquid vinegar with solid bicarbonate of soda.

About this activity

Olympia and her daughter Viola explore how bicarbonate of soda reacts with different liquids from around the house. Some fizz vigorously, others bubble gently, and some substances don’t appear to react at all. These simple chemical reactions introduce the idea that substances can react together to make a new substance, and are an excellent starting point for looking closely at the world around us. This experiment can be a little messy, but that's part of the fun.

When bicarbonate of soda reacts with substances like vinegar, carbon dioxide is given off as a gas, which forms the bubbles you see as the reaction fizzes. Experimenting with different liquids shows how some have certain things in common with each other. Acidic liquids cause fizzing while some don’t react. After exploring the different liquids, Olympia and Viola use this fizzing reaction to make a balloon inflate itself with carbon dioxide on top of a bottle.