DIY Lush Bath Bombs and the Science Behind the Fizz

My 12-year-old son has had a headache for the past two months. Fast forward five doctor appointments later, and we now think he has a concussion. He found baths soothing and he likes the Lush bath bombs that his sisters gave him for Christmas. They’re pretty expensive at $7 each, so we decided to make them ourselves.

An interesting Teachable Moment is the science of bath bombs. My son noticed that when he’s in the bath as the bath bomb gets crazy fizzy, that he feels a cold sensation coming off from the bomb. What is that? I think it’s the carbon dioxide gas that is generated from the chemical reaction.

When baking soda and citric acid are mixed and are then put in water, they undergo a chemical reaction. These bubbles that make the water become so fizzy are made of carbon dioxide gas.

DIY Lush Bath Bomb Recipe

• 1 cup baking soda
• 1/2 cup citric acid
• 1/2 cup Epsom salts
• 1 teaspoon water
• 2 teaspoons essential oil
• 3 teaspoons olive oil or melted coconut oil
• 5 to 15 drops food coloring of any color you want or more (more food coloring makes a stronger color in the bath)

• two bowls
• whisk
• bath bomb mold
• wax paper
• towel

Mix the dry ingredients in one bowl and the wet ingredients in the other smaller bowl. Mix well. If you are using the coconut oil, melt that first in a ceramic bowl and add to the wet ingredient bowl. You’ll have to work a little faster than if you use olive oil though.

We tried different combinations of essential oils as well. Peppermint feels invigorating and our bath testers commented on a tingling feeling from it. We also tried a combination of citrus-scented essential oils: sweet orange, grapefruit, lemon, and lemongrass. They were a hit. Lavender is my personal favorite but it gives an old fashioned “grandma” scent association to my kids. Perhaps mix your lavender with another scent.

Set up your unmolding area. Fold a fluffy towel in half and then cover with wax paper. You will be unmolding your bath bombs onto this to dry overnight.

Pour the wet ingredients over the dry and mix thoroughly. If there is a slight reaction, don’t worry. Just keep mixing but don’t compress the mixture. You want it nice and fluffy.

The tricky part of this entire operation is molding and unmolding the balls. We found that:

• Make sure the mixture is fluffy.
• Overfill each half of the mold and then press together gently.

• Carefully unmold onto the wax paper.

• The DIY Lush bath bombs will flatten on the bottom. If this bothers you, rotate the spheres as they dry.

• Let the bath bombs dry and then they are ready to use!

p.s. My daughter went really fancy on her third try. She split the recipe into four different bowls for four different colors and then molded her bath bombs.

p.s. I found the least expensive prices for supplies on Amazon.

Citric Acid, 1 pound for $4.49

Epsom Salts, 4 pounds, $5.36

Essential Oils, 6 for $12.89

Food Coloring, 4 Neon colors for $7.25

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