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Fizzy planets

By Jasmine Fellows, 3 November 2022

Which fizzy bath bomb is your favourite?

These bath bombs are crafted mini models of your favourite planets! We promise they’ll smell better than Uranus.

You will need

• Bicarb soda
• Citric acid
• Food colouring
• An essential oil suited to bath use, e.g. lavender, peppermint
• Bowls
• Spoon
• Sphere bath bomb mould (optional, available from craft stores)

What to do

1. Select a planet (or other celestial object) to make. Take inspiration from the images below, or you can do your own research!
2. In a bowl, mix equal parts bicarb and citric acid. To get the correct amount for your mould, heap one half of the mould with bicarb, and the other half with citric acid then pour them both into the bowl.
3. Add a drop or 2 of an essential oil. Mix the oil through evenly.
4. Split the mixture into as many bowls as you’d like colours.
5. Add a different food colouring to each bowl. Use the least amount of food colouring possible to achieve the colour you want. Keep it to 2 to 4 drops, mixing it in drop by drop. Too much liquid will make the bath bomb sticky and hard to work with.
6. Fill the bath bomb mould trying to match the colours to the planet. Pack each half tight, then press them together to dry.
7. Leave the bath bomb to dry for 4 hours.
8. Carefully remove the bath bomb from the mould. Now, it’s ready to use in the bath!

Planet inspo

Get creative! You don’t have to stick with planets or even their true colours. You can make other celestial objects such as moons and dwarf planets.

Did you know?

It’s true. Uranus stinks! As well as giving farts a distinctive odour on Earth, hydrogen sulfide gas has been found in the cloud tops of Uranus

If you’re after more science activities for kids, subscribe to Double Helix magazine!