how do soft drinks become unfizzy?!

Best Answer - Chosen by Voters

the carbon dioxide that gives the soda it's fizz escapes into the air if the container is left open.

Soda goes flat because the carbonation used to make it fizzy is put into the soda under pressure. Once the cap is removed, it is no longer under pressure and the CO2 gas can escape. The bubbles you see are made of CO2 (Carbon Dioxide). Once the CO2 is gone it is flat.

I hope this helps. :-)

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