Aim: to demonstrate a chemical reaction that produces a gas when reactants are in the correct state.

Bath bomb demonstration video

Make a bath bomb with your primary students to investigate gases, and changing materials.

These resources were created for the Cambridge science festival 2013. The bath bomb demonstration video shown here was taken from the Primary Science Demonstrations series.

If you teach primary science, see the headings below to find out how to use this resource:

Skill development

Children will develop their working scientifically skills by:

  • Using appropriate scientific language and ideas to explain, evaluate and communicate their methods and findings.
  • Drawing conclusions and raise further questions that could be investigated, based on their data and observations.
  • Asking their own questions about scientific phenomena.

Learning outcomes

Children will:

  • Create different mixtures using the same starting materials.
  • Observe that some materials will dissolve in liquid to form a solution.
  • Explain that some changes result in the formation of new materials and that this kind of change is not usually reversible.

Concepts supported

Children will learn:

  • That some reactions result in the formation of different products, and that these reactions are often irreversible.

Suggested activity use

This activity could be used as a whole class investigation, with children working in small groups to create their own bath bombs. Children could investigate further by determining the effects of varying the ratios of the mixtures used to create the bath bombs.

Practical considerations

You will need to source the equipment for this experiment, ensuring that you have enough for multiple bath bombs per group.

Also, please take into account any health and safety considerations, particularly with regards to allergies.