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Bath Bomb Experiment

Make your bath time more fun with this cool and useful experiment!

Check Out the Youtube Video Here, for in depth steps and instructions:

Topics: Chemical Reactions

Difficulty: Easy to conduct and see reactions


  • Measuring Spoons

  • Mixing bowls

  • Baking Soda

  • Citric Acid

  • Cornstarch

  • Water

  • Spoon

  • Food Coloring (optional)

  • Scents/Essential Oils (optional)

  • Molds to shape the bath bombs (optional)


1. Mix ½ cup baking soda and ¼ cup cornstarch in a large mixing bowl. Use a mixing spoon to break up any clumps. Set the citric acid aside and do not mix it in.

2. Add any essential oils or scents that you desire, this step is optional if you do not want a scent.

3. Mix in the food color a few drops at a time into the dry mixture using the spoon. The more drops you use, the deeper and more saturated the color will become. This is also optional if you wish to have a non-colored bath bomb.

4. Add water at about half a teaspoon at a time, stirring the mixture in after each addition. Water should be added until the mixture has a texture of damp sand and can be held in a tight clump

5. Add ¼ cup of the citric to the mixture and mix it in thoroughly.

6. Using the mould or your hands, pack together the mixture in a ball

7. Let the bath bomb sit overnight to dry

8. Place your bath bomb in the water and watch the fizzy reaction occur!

How It Works:

Once we drop the bath bomb into the water, we see that a fizzy reaction begins to occur. As the baking soda interacts and dissolves into the water, it is then able to react with the citric acid. With this reaction, we see that a gas called carbon dioxide is produced. As it is a gas, it desires to escape from the water, and rise up. This causes fizzing and bubbling to occur. See the reaction equation below, which illustrates what is happening:

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