DIY Unicorn Bath Bomb Activity With Chemistry Lesson

We loved making our Zoey and Sassafras inspired Unicorn Soaps so much we decided to try a bath bomb too! We know this activity would be Zoey approved because bath bomb making involves a lot of science and chemistry, and her thinking goggles would come in very handy while figuring out all the steps involved in making these Unicorn Bath Bombs.


unicorn horn bath bombs

If you have spent any time visiting STEAM Powered Family lately, you know we are loving making bath bombs as part of our chemistry labs. It’s a great science project, but involves a lot of creativity. Plus it is a ton of fun and the results are always used and loved as gifts. Meaning there is no waste! Yeah!

Zoey and Sassafras

If you haven’t already read the Zoey and Sassafras books, you need to check them out! They are fantastic STEM fiction chapter books that always get my kids so excited to do science experiments. This series is a favourite of my youngest and he anxiously awaits the release of each new book in the series.

The latest book in the Zoey series is Unicorns and Germs. It features a magical unicorn named Tiny who is anything but Tiny. He also has an infected injury. So Zoey needs to break out her thinking googles and figure out how to help her magical friend. It involves a lot of scientific investigations until she finds the solution.

The book inspired some fun investigations of our own! You can read more about our petri dish experiments and Unicorn Horn Soap making project here. But this time we decided to set up our chemistry lab and create some bath fizzy fun with some Unicorn Bath Bombs.

Chemistry Lab unicorn horn bath bomb project

Zoey Approved Science Of Bath Bombs

Zoey takes her scientific investigations very seriously. So when doing this activity with your little unicorn loving scientists it is important that they take the chemistry lab lessons just as seriously as Zoey would. You never know when a magical creature might come calling for help and rely on your science skills.

An Acid-Base Reaction

So first up, bath bombs are an acid-base reaction. Just like some of our favourite experiments in the past like Bottle Rockets or Hatching Dino Eggs. In this recipe our base is Baking Soda and our acid is Citric Acid.

Now our astute little scientists will notice that when they combine these powders nothing happens. There is no reaction. When we mix our vinegar and baking soda we get an instant, big reaction. With bath bombs we need to add one more ingredient to trigger the reaction, water. Once water is added, the reaction will start and our Unicorn Bath Bombs will start bubbling and fizzing away. This is important to understand because if your bath bombs start to erupt too early, it could be there is too much humidity in the air, or you may have water on your hands from not drying them properly… not that I have ever done that…

Making Oil and Water Get Along

Now there is two strange looking ingredients you may not recognize. SLSA is a surfactant that helps create a luxurious, foamy bath from your bath bombs. The other is a very important ingredient called Polysorbate 80. This is an emulsifier. As we all know, oil and water do not like to mix. Polysorbate 80 helps convince the oils in our bath bomb (including the colours), to mix nicely with our bath water. Without polysorbate 80 your oils and colours will float on the top of your bath water like scum, and no one wants that!

With our science lesson completed, it’s time to make some Unicorn Bath Bombs!

DIY Unicorn Bath Bomb Recipe For Kids

DIY Unicorn Bath Bombs Recipe

1 cup baking soda
1/2 cup citric acid
1/2 cup cornstarch
1/4 cup SLSA
1/4 cup Epsom salts
1 tablespoon Polysorbate 80
1/3 cup coconut oil
10-20 drops of Geranium essential oil
1 teaspoon of hibiscus oil (or other floral scent)
1 tablespoon each of Teal, blue, pink, purple and gold mica powder
Spray bottle of rubbing alcohol
1 large mixing bowl
6 smaller mixing bowls
Unicorn Horn Popsicle Mold

Unicorns and Germs (Zoey and Sassafras)Zoey and Sassafras Books 1-6 Pack1pc 6 Section Swirl Ice Pop Maker Mold Popsicle Dessert Cream Frozen Pops TreatsMilliard Citric Acid 2 Pound - 100% Pure Food Grade NON-GMO Project VERIFIED (2 Pound)Sodium Lauryl Sulfoacetate (SLSA) (1 lb.) by Pure Organic Ingredients, Eco-Friendly Packaging, Ideal Bath Bomb Additive, Gentle on Skin, Surfactant & LathererPolysorbate 80 (Solubilser) 125 gramsMica powder – Soap Making Kit – Powdered Pigments Set – Soap making dye – 24 coloring - Hand Soap Making Supplies - Resin Dye - Mica Powder Organic for Soap Molds - Bath Bomb Dye Colorant – Makeup Dye

How To Make Unicorn Horn Bath Bombs

In a large mixing bowl, add baking soda, citric acid, SLSA, cornstarch, and Epsom salts.

In a small mixing bowl add coconut oil, polysorbate 80, geranium essential oil and hibiscus oil. Mix well. Then add to the large bowl and mix everything together. Mix all the ingredients until it is the texture of wet sand and holds together when pressed in your hand. This step is best done with your hands. Use disposable gloves if needed.

Separate the mixture evenly into 5 smaller bowls.

Colour each bowl one of the colours by adding the mica powder and mixing thoroughly. Our five colours are: gold, teal, blue, pink and purple. You can change this to your preferred colour combination if you wish.

In each cavity of the mold, add your first color and press firmly into the mold. Repeat with the next 4 colors. We made thin layers to show off the pretty layered look. This takes time though and your mixture may start to dry out by the time you get near the top. If this happens spray the mixture with a bit of rubbing alcohol to moisten.

Repeat layering the colours until the mold is full. Make sure you are pressing firmly.

Leave the molds to harden for at least 48 hours. They need to be completely dry, so if you touch the bottom and feel any dampness, let them dry for 24 additional hours. The length of drying time will vary based on your environmental conditions.

When ready to remove your Unicorn Bath Bombs from the molds, place a large plate or cutting board over the mold and gently flip over. CAREFULLY allow each mold to slide onto the plate or cutting board. The more layers you add to a bath bomb mold, the more fragile they become, so take your time!

If needed, you can gently tap the sides to help release it from the mold.

Store in an airtight container until ready to use. When you are ready for a unicorn bath, drop one in the bath and enjoy! These smell AMAZING!!!

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