Why does soda fizz?

When your child asks, here's how to answer — in their words, and in yours.

For your child

Soda fizzes because tiny little bits of special air are mixed into it! When you open the bottle, they get excited and quickly try to escape, making all those bubbles you see and hear.

Heads up

The answer simplifies 'carbon dioxide gas' into 'special air' and avoids terms like 'dissolved' or 'pressure' in a technical sense. These concepts can be introduced later when the child has a basic understanding of gases and how they behave.

For you

Soda fizzes due to dissolved carbon dioxide gas. Under pressure in the sealed bottle, more carbon dioxide can dissolve in the liquid than at standard atmospheric pressure. When the bottle is opened, the pressure drops, and the carbon dioxide quickly comes out of solution, forming bubbles and creating the characteristic fizz.

They might ask next

Where does that special air come from?
Why does soda stop fizzing after a while?
Do other drinks fizz too?

Whyzard answers your child's own questions — out loud, in words they'll understand.