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St. Patrick’s Day Leprechaun Toothpaste

By March 13, 2020No Comments

Leprechaun Toothpaste 

Even busy little leprechauns need to brush their teeth! My littles loved watching the green “toothpaste” ooze when the elements were brought together. The consistency was pretty cool, too! This is a perfect experiment for any kiddos who like sudden, exploding type reactions.  


Small container (we used a mason jar which proved to be tall for the explosion to go over- so if you want containment, opt for a mason jar) 

6% hydrogen peroxide (20 volume developer) – must have this type 

Green food coloring 

Liquid dish soap 

Baking dish 

Dry active yeast 

Lukewarm water 


Note: This first part should be done by an adult, to handle the hydrogen peroxide since it can bleach hair and clothes and cause possible skin irritation. If it comes in contact with skin, wash off immediately. If it comes in contact with eyes, flush with water. 

Mix 2 tablespoons of hydrogen peroxide , a few drops of green food coloring and a few drops of liquid dish soap in the empty container. 

In another small dish, mix ¼ teaspoon dry active yeast with ½ tablespoon warm water.  

Carefully add the yeast mixture to the peroxide mixture. The result is quick to happen! The bubbly foam is okay to touch, the peroxide does break down in the reaction. Soapy water is what is left. My little guy was amazed at how quick the experiment reacted and was eager to touch the foam that formed. 

The reaction was exothermic, which means it produced heat. Hydrogen peroxide easily decompresses into oxygen gas and water. Yeast acts as a catalyst in this reaction, which means the yeast makes the reaction happen more quickly. When the yeast comes into contact with the hydrogen peroxide, it produces gas very quickly. The oxygen bubbles out of this solution, making foam.  

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