Ever wonder why bath bombs fizz when they hit the water? It all comes down to a chemical reaction! When the bath bomb dissolves, the ingredients inside react with the water, releasing gas and creating bubbles.

This reaction is called an acid-base reaction. The acid (citric acid) and the base (baking soda) mix with water and form carbon dioxide gas, along with salt and water. This gas is what makes the bath bomb fizz!

In this project created by Catherine, a member of the Rosie Innovators STEM program for young women in high school, you’ll experiment with acids and bases to see this reaction up close. Ready to explore? Gather your materials and follow the instructions below!