Mystical Rainbow Unicorn Bath Bombs

We love bringing a little magic and fantasy to our learning activities. Over time we have discovered that bath bombs are the perfect way to foster creativity and a little magic with our creations that even my crafting adverse children embrace with enthusiasm! This week we decided to make Unicorn Bath Bombs with a new salt recipe.

Unicorn Bath Bombs

Unicorn bath bombs in a rainbow of colors. Overlay text Unicorn Salt Bath Bombs with Chemistry Lesson for kids

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Remember when we made Dragon Bath Bombs? Or Fairy Bath Bombs? Oh or what about all the amazing Harry Potter inspired bath bombs?

Not only do we love fantasy and magic around here, we also really love making (and using) bath bombs! Over time I have come to see what an incredible opportunity bath bombs have provided us to not only learn some fascinating lessons in chemistry and science, but also to spend time bonding, laughing and creating.

Best of all bath bombs are a zero waste craft. We love using our bath bomb creations and our friends and family are always excited when we gift our creations.

So if you haven’t tried making bath bombs, why not?

Today we are jumping into a new fantasy inspired bath bomb with a Unicorn Bath Bomb that has the most gorgeous colours. We are also exploring a new recipe. We are calling it a salt bath bomb recipe. It uses quite a bit of Epsom salts and clay to create an extra hard bath bomb that has the benefits of salts in the bath.

Unicorn Bath BombS Recipe & Supplies


2 cups baking soda (sodium bicarbonate)
1 cup citric acid
1/4 cup cornstarch
2 tablespoons bentonite clay
2 tablespoons Milk and Honey Epsom salts
1/3 cup coconut oil
1 tablespoon polysorbate 80
2 tablespoons cocoa butter
10-20 drops each cardamom and cedarwood essential oil
1-2 tablespoons each of purple, blue, pink, yellow & green mica colorant
1 teaspoons of biodegradable cosmetic glitter in each of the smaller bowls
Stainless steel bath bomb molds
Mini muffin tin (optional)
Disposable gloves (optional)
1 large mixing bowl
1 microwave safe cup or bowl
5 small bowls

Sodium Bicarbonate (Baking Soda) (2 lb.) by Pure Organic Ingredients, Eco-Friendly Packaging, Highest Purity, Food & USP GradeCitric Acid (4 oz) by Pure Organic Ingredients, Eco-Friendly Packaging, All-Natural, Highest Quality, Pure, Food Grade, Non-GMOAnthony's Organic Cornstarch, 2lbs, Gluten Free, Vegan & Non GMOBentonite Clay Food Grade Powder - 2 LB Pure Natural Powder for Internal and External Use - Great For Detox,Toothpaste, In Smoothies and More - Heal Damaged Skin - DIY Clay Face MaskDr. Teal's Epsom Salt Soaking Solution, Soften & Nourish with Milk and Honey, 48oz, Pack of 2Viva Naturals Organic Extra Virgin Coconut Oil, 16 OuncePolysorbate 80 (Solubilser) - 500gOrganic, Unrefined, Raw NATURAL COCOA (CACAO) BUTTER 1 LB (16 oz) BLOCK Best Price Highest Quality, Bulk Rich Chocolate Aroma For Lip Balms, Stretch Marks, DIY Base for Body Butter & Soap Making (USA)Epoxy Resin Color Pigment - 50 Color Mica Powder Epoxy Resin Dye, Cosmetic Grade Soap Colorant for Soap Making Supplies, Natural Slime Coloring Soap Dye for Paint,Nail Art,Bath Bomb (0.18oz Each Bag)Minke Biodegradable Glitter (Multi Color Combo)Stainless Steel Bath Bomb Molds Professional Set of 3 Sizes. Heavy Duty Metal, Dent and Rust Proof by Healthy Home Helper.


*A NOTE ON GLITTER – Glitter has become very controversial due to the negative impacts on the environment, but I know many of you still love a little sparkle in your projects! When it comes to glitter, I believe it is always optional. None of my projects require it. But if you decide you do want a little sparkle and shine in your creations, I highly recommend using a biodegradeable glitter. There are lots of fantastic options available.


In a large mixing bowl, add the dry ingredients: baking soda, bentonite clay, citric acid, Milk and Honey Epsom salts and cornstarch. Mix all of the dry ingredients together. Use caution not to be too aggressive when mixing. Citric acid is a bit irritating if it becomes airborne.

In a microwave safe cup add the coconut oil and cocoa butter. Melt in the microwave just until the coconut oil is liquid. The cocoa butter may not be liquid, but it will be softer and easier to mix. Both of these ingredients help moisturize the skin and act as binding agents for the bath bombs.

Now to the liquids, add the polysorbate 80 (our emulsifier, see the science section for details), and essential oils. Mix.

Next add the liquid mixture to the large bowl of dry mix. Start mixing everything together with your hands (use gloves if you prefer). Once it holds together like wet sand it is ready for coloring.

Separate the mixture evenly into 5 bowls. Into each bowl sprinkle a teaspoon of biodegradable cosmetic glitter. Now, mix purple mica into the first bowl, the blue in the second, the yellow in third, the pink in fourth and green in the last bowl. Mix each bowl well to evenly disperse the colours. You may wish to use gloves so you don’t colour your hands.

It’s time to pack the molds!

Layer the colours into the molds in whatever pattern you prefer. Go until it is loosely heaped. Repeat on the other side. Now bring the two halves together, twisting until the molds connect. Do this over a bowl to collect the bits that fall. Now tap the ends and sides before carefully lifting off one end of the mold to release your bath bomb.

Set in a mini muffin tray to prevent rolling about. Trust me, this makes it so much easier to carry them around! Leave them in a warm, dry place to set for minimum 24 hours. I usually prefer to wait 48 hours to ensure they are nice and hard.

Unicorn Salt Bath Bombs For Kids

The Science of Bath Bombs

The basic chemical reaction in bath bombs is an acid-base reaction between the baking soda and citric acid. We have tried other acids like buttermilk in the past, but citric acid really does give the best fizz.

In their dry form, the acid and base don’t react. They need that magical unicorn ingredient… WATER to kick start the fun, fizzy chemical reaction.

In this recipe we have two binding agents, coconut oil and cocao butter, plus bentonite clay which help to give the bath bombs their structure and sturdiness. Plus coconut oil and cocao butter help moisturize the skin. But, since they are oils they don’t mix with water. Which is why we need this next ingredient.

Polysorbate 80 is an emulsifier. It helps oils mix with water. This is so important with bath bombs. If you don’t use polysorbate 80 the oils, fragrances and colours will float in a scummy later on the top of your bath water sticking to everything and making a big mess.

Plus the science of this is really cool. Check out our making moon dough recipe to see a video of polysorbate making water and oil mix.

Finally we have Epsom Salts which can help ease muscle pain.


This bath bomb recipe includes clay and salt which both love to draw in moisture. As we noted above, water triggers the reaction in the bath bomb. If you are struggling with this bath bomb recipe it is likely due to those ingredients. Try one of our many other bath bomb recipes that don’t use clay or salt, and you should have success! I’ve listed a few below you can check out, or just search for bath bombs. We have LOTS!

Aren’t the colours in this Unicorn Bath Bomb gorgeous? Perfect for a magical chemistry lesson follow by a relaxing bath, enjoying your creations.

Happy Bath Bomb Making!

Unicorn Salt Bath Bombs Recipe and chemistry lesson for kids


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