Question about variables in the Bath Bomb project

[CHVA]

Hi, Sorry for replying to this after two years haha. I have been wondering why cornstarch is used as a filler? What is a 'filler' and why cornstarch specifically. What reaction does it undergo with the water to make it more fizzy? Thank you very much!


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[ubtfulcoast]

Cornstarch is used as a filler to bulk up, stabilize, and prevent clumping. It doesn’t react with water; the fizz comes from the reaction between citric acid and baking soda, producing carbon dioxide.