STEM Activities: DIY Bath Bombs

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Join role models Lesley Chard, Denise Hodder, and Collette Garland as they each guide you through the fun process of making DIY bath bombs! Using kits previously sent to STEMforGIRLS participants, they demonstrate how to create these fizzy, fragrant creations step by step. Don’t worry if you don’t have a kit—you can easily do this activity at home! The tools and ingredient list are provided below, so you’re ready to dive in. Watch all three videos below for unique tips and techniques from each role model, and get inspired to customize your own bath bombs!

DIY Bath Bomb Instructions

Tools Needed:
Large mixing bowl

Small bowl or measuring cup
Whisk or fork

Spray bottle (optional, for even wet ingredient application)
Measuring spoons and cups

Silicone molds, bath bomb molds, or any small containers (e.g., muffin tins)
Gloves
Ingredients:

Dry Ingredients:

1 cup citric acid

1 cup baking soda
½ cup Epsom salt or potassium chloride

Dry Ingredients:

2–3 teaspoons water (or a carrier oil like coconut, almond, or jojoba)

Optional: 10–15 drops of essential oils (e.g., lavender, eucalyptus, or orange)
Optional: Food coloring or bath-safe colorants
Instructions:
1. Prepare Your Workspace:
Clean and sanitize all tools and surfaces to avoid contamination.

Gather your ingredients and tools for easy access.
2. Mix Dry Ingredients:
In a large mixing bowl, combine the citric acid, baking soda, and Epsom salt (or potassium chloride).

Whisk thoroughly to remove any clumps and ensure an even mixture.
3. Add Color and Fragrance:
If using food coloring or essential oils, add them to the dry mixture.

Mix well until the color is evenly distributed. Wear gloves if mixing by hand to avoid staining your skin.
4. Prepare Wet Ingredients:
In a separate small bowl or measuring cup, mix the water (or carrier oil) with any additional colorants or essential oils.

For even application, transfer the wet mixture into a spray bottle if desired.
5. Combine Wet and Dry Mixtures:
Slowly add the wet mixture to the dry ingredients, stirring constantly.

Use a spray bottle for more control to prevent the mixture from fizzing prematurely.
The mixture should resemble wet sand and hold its shape when squeezed. If it’s too dry, add a tiny amount of water (a few drops at a time).
6. Mold the Bath Bombs:
Firmly pack the mixture into your molds. Overfill slightly, then press the halves (if using bath bomb molds) or the surface of your mold together tightly to compress.

Gently scrape off any excess mixture for a smooth edge.
7. Set and Dry:
Allow the bath bombs to set in the molds for 24 hours in a cool, dry place. For faster drying, refrigerate them for a few hours before allowing them to finish air drying.
8. Unmold and Store:
Carefully remove the bath bombs from their molds.

Store them in an airtight container or wrap them individually in plastic wrap to keep them fresh. Keep in a cool, dry place until ready to use.
To Use:

Drop a bath bomb into a tub of warm water. Watch it fizz and release its fragrance and color as you relax.

Tips for Customization:
Add dried flowers, biodegradable glitter, or herbal teas for an extra luxurious touch.
Experiment with different essential oil blends for unique scents (e.g., peppermint and eucalyptus for a refreshing boost).
Create multicolored bath bombs by layering different colored mixtures in the mold.
Troubleshooting Common Issues:
Crumbly Bath Bombs: This can happen if the mixture is too dry. Add small amounts of liquid (a spray or a few drops) until it holds together.
Premature Fizzing: Often caused by too much moisture. Add wet ingredients gradually and avoid working in humid conditions.
Cracking: Over-packing molds or uneven drying can lead to cracks. Ensure a uniform mixture and avoid overfilling molds.
Sticking to Molds: Lightly grease molds with a small amount of oil or clean them thoroughly before use.

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