Create fizzy, colorful bath bombs that hide a secret little toy inside! You'll learn about the chemical reaction between acids and bases while making a magical bath treat.

Tools

• mixing bowl
• whisk or spoon
• bath bomb molds (or plastic Easter eggs)
• measuring spoons

Materials

• baking soda (1 cup)
• citric acid (1/2 cup)
• cornstarch (1/4 cup)
• epsom salt (1/4 cup)
• water (2 tbsp)
• vegetable oil or coconut oil (2 tbsp)
• bath bomb coloring or food coloring (5 drops)
• essential oil or fragrance oil (5 drops)
• small plastic toys or themed charms (1 per bath bomb)

Safety

• Adult supervision required when handling citric acid to avoid eye irritation.
• Ensure the small toys used as surprises are age-appropriate to avoid choking hazards.
• Wash hands thoroughly after handling fragrance oils.
• Do not eat or drink any materials used in this project.
• Protect work surface. Materials may stain clothing.
• Adult supervision required for children under 8.

Steps

1. In a large mixing bowl, combine the baking soda, citric acid, cornstarch, and epsom salt. Whisk together until there are no lumps.
2. In a separate small bowl, mix the oil, water, coloring, and fragrance oil together.
3. Slowly add the liquid mixture to the dry ingredients one teaspoon at a time. Stir gently; if the mixture starts to fizz, stop adding liquid and stir quickly.
4. Continue mixing until the texture feels like damp sand—it should hold its shape when you squeeze it in your hand.
5. Fill the bottom half of your mold or plastic egg halfway with the mixture.
6. Place one small toy or charm right in the center of the mixture.
7. Carefully pack more mixture on top of the toy until the mold is full and the toy is completely covered.
8. Press the two halves of the mold together firmly and let it sit for at least 24 hours to harden completely.
9. Gently pop the surprise bath bomb out of the mold and enjoy it in a warm bath!