Most kids love a fizzy bath bomb. And they will sure love making them as much as my daughter did! They are very easy to make and they and an excellent kitchen/science project to kill time in the afternoon - or when your children refuse to do any more maths or regular schoolwork! Make them colourful, make them smell nice and you can even give them out as presents to your friends and family. 

We have followed the BBC recipe and video, which is worth watching before you start.

Ingredients

Makes 4 half-ballsPrep 30 mins, plus 2-4 hrs setting

• 100g bicarbonate of soda
• 50g citric acid
• 25g cornflour
• 25g Epsom salt (optional)
• 2 tbsp oil – such as sunflower, coconut or olive oil
• ¼ tsp essential oil, such as orange, lavender or chamomile
• a few drops of liquid food colouring
• orange peel, lavender or rose petals, to decorate (optional)

You will also need

• mixing bowl
• whisk
• plastic moulds - we used silicon cake and cupcake cases, sand moulds. You can use other things such as yoghourt pots and cookie cutters placed on a tray. 

Method

1. Put the bicarbonate of soda, citric acid, cornflour and Epsom salt in a bowl, then whisk until fully combined.

2. Pour the base oil, essential oil and food colouring in a small bowl. Mix together well, combining the oil with the colouring as much as possible.

3. Very slowly add the oil mixture into the dry ingredients a little at a time, while whisking all the time. When all the oil is added, add a few tiny drops of water and whisk again (it will fizz when you add the water, so mix it in quickly). You're looking for the mixture to slightly clump together when pressed in your hand and keep its shape – it shouldn't be too wet. A word of warning! if you add too much water the mixture will keep growing in the moulds as the citric acid and bicarbonate soda will activate. 

4. If you're adding peel or flower petals to decorate, drop them into the bottom of your chosen mould. Pack your mixture tightly on top, pressing down and smoothing out the top with a teaspoon.

5. Leave your bath bomb in the mould to dry for 2-4 hr. Once dry you are ready to remove them from the mould, drop into the bath and watch it fizz away!