Mentos.
Shake it
club soda
you can use Mentos and baking soda
Add vinegar
pepsi
Carbonated soda has CO2 in it because the gas make the soda bubble and fizz.
The fizz is put into soda by pumping carbon dioxide into it under pressure.
Carbon dioxide gas puts the fizz in soda water.
Baking Soda is most likely the answer to this question.
it will fall and it will explode in fizz and make a big mess
from the carbonation
duhr