The Science of Bath Bombs

Bath Bomb Project


In order to make their characteristic fizz, bath bombs contain two important chemicals – sodium bicarbonate (NaHCO3) and citric acid (C6H8O7). Sodium bicarbonate is a base, whereas citric acid is an acid. When an acid and base react together they produce a salt, water and carbon dioxide – the source of the fizz!

The chemical equation for this reaction is: 
NaHCO3(aq) C6H8O7(aq)  Na3C6H5O7(aq) + H2O(l) + CO2(g)

Can you think of any other examples of acid-base reactions?


In order for the chemical reactants to come together, they must first dissolve into the solution (the bath water). Dissolving is an example of a physical reaction, since the chemicals change state from a solid to being dissolved in a liquid.

Can you think of some methods of speeding up the rate at which the chemicals dissolve? At school, you may have learnt about the effects of temperature, surface area and mixing. You can even test these theories yourself at home using some sugar cubes and water!