Featured Project: Bath Bomb Chemistry

    Create your own bath bombs with your favorite fragrances and colors, too!   

    Bath bombs are fun to use and even more fun when you make them yourself because you can choose your favorite fragrance and color!  And it’s a cool science experiment, too!

    How does it work? 

    Two of the main ingredients, sodium bicarbonate and citric acid, make the bath bomb fizz when placed in water. These chemicals are inert (chemically inactive) when they are dry powders, but when they dissolve in water the citric acid reacts with the sodium bicarbonate to form sodium citrate and carbon dioxide. 

    The sodium citrate stays in solution and you don’t really notice it, but the carbon dioxide bubbles out as a gas that helps the bath bomb break up. This lets the perfumes and oils that make up the rest of the bath bomb mix with the bathwater. 

    Now let’s make some bath bombs…

    Dry ingredients 

    • 1 cup baking soda (sodium bicarbonate) 
    • 1/2 cup citric acid (can be purchased at Amazon or Walmart) 
    • 1/2 cup Epsom salts 

    Liquid ingredients 

    • 1 tsp. water 
    • 3 tsp. olive oil
    • 2 tsp. essential oil or other fragrance (optional)
    • food coloring (optional) 


    • bowl 
    • whisk 
    • jar 
    • bath bomb mold (can be purchased at Amazon or Michael’s or be creative and use household items like ice cube trays, muffin tins or silicone molds) 


    1. Whisk all of the dry ingredients together in the bowl. 

    2. In a jar, mix all of the liquid ingredients together including the essential oils, fragrances and colors if you are using them.

    3. Add the liquid mixture to the dry mix one small spoonful at a time. Mix thoroughly with the whisk before adding more liquid.

    4. Once all of the liquid is incorporated, tightly pack the mixture into a bath bomb mold and let it dry.

    After the bath bombs are dry, its time to try them out in the bath and see the chemistry in action!


    Click here to find the original source for the photos and bath bomb recipe – it’s a great site for finding fun projects to try at home!