Bath Bombs

Create your very own Bath bomb and make bath time more fun and exciting whilst exploring the science behind the chemical reaction.



  • Selection of aromatherapy oils
  • Non-latex gloves
  • Tablespoons
  • Beakers (1 per child)
  • Bicarbonate of Soda powder (try
  • Cornflour
  • Citric Acid powder (try
  • 6 x Garden spray bottles
  • Small (100ml) plastic tubs with lids (1 per child)
  • Wooden tongue depressors (1 per child)
  • Food Colouring
  • Plastic Pipettes


(The order in which bicarbonate of soda, cornflour and citric acid are added doesn’t matter)

  1. Measure 2 tablespoons of bicarbonate of soda into your plastic cup
  2. Measure 1 tablespoon of cornflour into your cup
  3. Add 1 tablespoon of citric acid to your cup and stir
  4. Add a couple of drops of food colouring and mix well
  5. Now add a few drops of some fragrant oil and mix
  6. Add water onto your mixture using a spray bottle a little at a time until it starts clumping together and looking a little like breadcrumbs
  7. Tip the mixture out into your bath bomb mould and press down
  8. Leave your mixture to set
  9. When it’s ready, pop it in the bath and watch it fizz!

The Science

When the bath bomb dissolves in water, there is a chemical reaction between the citric acid and the sodium bicarbonate. The result is called “sodium citrate”. During the reaction, carbon dioxide is released.
This causes the ‘fizzing’ that you see, similar to that in fizzy pop.


Health and Safety

Citric Acid can be an irritant and will sting if it gets into an open wound or an eye. Irrigate with sterile water if needed. It is also advisable that children with sensitive skin wear gloves for this experiment and do not use the bath bomb in the bath themselves. It is also a good idea to label the bath bomb so that its contents are clearly displayed.