Three bath balls, various colours

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. Pouring white powder into a bowlIn 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. Four bowls with different coloured powderAdd 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. Putting coloured powder into mouldFill 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. Three bath balls, various coloursCarefully 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.

  • Planet with red, blue and white
  • Blue planet Neptune
  • Red planet Mars
  • Model of Earth with cut-out section exposing Earth's core

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

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

By submitting this form, you give CSIRO permission to publish your comments on our websites. Please make sure the comments are your own. For more information please see our terms and conditions.

Why choose the Double Helix magazine for your students?

Perfect for ages 8 – 14

Developed by experienced editors

Engaging and motivating

*84% of readers are more interested in science

Engaging students voice