Making bath bombs

Making bath bombs uses the reaction of acid plus alkali producing a gas (carbon dioxide) plus water. The reaction doesn't take place until the chemicals have water added.

Bath bombs make excellent presents and are fun to make. The ingredients used are things that are relatively safe and are found around the house or in household products (citric acid is in lemons) so young children can take part in making these. They should wash their hands after touching the chemicals and be old enough not to eat the ingredients. My four and seven year olds made these, with supervision from me.

Ingredients:
Sodium bicarbonate
Citric acid (we bought ours from Just a soap but I am sure that this can be brought elsewhere)
Almond oil (I am sure that other oils can be used)
Food colouring
Optional: essential oils or vanilla essence

Method:
Add 3 tablespoons to sodium bicarbonate to 1 tablespoon of citric acid in a dry mixing bowl. Mix well, add a few drops of food colouring to required colour. 

Add essential oils or vanilla essence. Be sparing with the vanilla-it contains water and will lead to the sodium bicarbonate and citric acid reacting. Large quantities will mean that there will be no acid and alkali left to react.

This is what happened when we added a large quantity of vanilla essence

Add almond oil slowly to combine. We started with 1 teaspoonful but needed to use rather more than this to make sure the mixture stayed together.
Put the ingredients in a model. We used doll's cups as well as a brought mould. The cups worked just as well.

Allow the bath bombs to dry then turn out into cupcake cases.
Store in boxes to give as presents.

Do label these as bath bombs and not for eating! I thought that the red bath bombs looked rather like coconut pyramids.

Put in the bath to start the reaction and watch the fizz!