Homemade Bath Bombs

Your Challenge: Use chemistry to make relaxing bath bombs!  Bath Bombs


2 C. Baking Soda

1 C. Cream of Tartar

2 Tbsp. Olive Oil

Food Coloring

Essential Oils

Water in a spray bottle

Silicone Ice Cube Trays

Mixing Bowl


Here’s How:

1. Mix 2 C. Baking Soda, 1 C. Cream of Tartar, 2 Tbsp. Olive oil, and choice of food coloring until you have a color you are happy with. Do not add too much food coloring to start. The food coloring should be added in little droplets and you must persevere in mixing it in. It should still look quite powdery once mixed.

2. Spray in 2-3 squirts of water. It will fizzle a little as the baking soda reacts with the water. As you start to mix it, it will feel a little more solid, like wet sand. Spray water a couple squirts at a time and continue to mix. You want to continue to add water until the mixture leaves a nice shape behind without crumbling too much. Be careful not to add too much water.

3. Mix in a few (2-3) drops of the essential oil.

4. Press the mixture into the silicon ice cube trays. Make sure to press down hard and pack the mixture in.

5.  The ice cube trays must sit for 1-2 days to ensure the bath bombs get hard over time.

6. Remove the bath bombs gently from the ice cube tray. If you find that they break apart, you didn’t add enough water. You can crumble it all again, spray with more water and try again.

7. Ask your parents if you can use it in the bath tub. Have a nice relaxing bath and watch the bath bomb dissolve in action! The bath bombs work best in warm-hot water.


Take It Further:

  • Try to dissolve your bath bomb in different temperatures of water. Which temperature works best?

How It Works:

When the bath bomb is placed in water, the baking soda and cream of tartar start reacting together in an acid-base reaction. When the cream of tartar and the baking soda react, they form new molecules. One of those new  molecules is carbon dioxide, which is a gas. The bubbles form from the sudden production of carbon dioxide gas molecules.

Fun Facts:

  • Bath bombs can help sooth muscles and they can have a wide range of ingredients. A few key ingredients that most homemade recipes have are baking soda and citric acid or cream of tartar. When baking soda and citric acid/cream of tartar are mixed and are then put in water, they undergo a chemical reaction.
  • Da Bomb Fizzers is a  business that was created by Caroline and Isabel Bercaw, and they came up with the idea when they were 10 and 11 years old! They started with $25 worth of ingredients to make a homemade bath bomb science experiment for an art fair. When they sold out of their product, they decided to reinvest and make more bath bombs to sell. Since then, their business investment has turned into a multi-million-dollar business.

Related Careers:  Chemist,  Food Scientist

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