Lesson Plan Title : Hydrogen Peroxide and Potatoes

Age Range:

Grade 9 through Grade 12 (High School)

Overview and Purpose:

Watching hydrogen peroxide foam when it comes in contact with certain materials is fascinating. But, does it always react that way and why? This lesson allows students to experiment and find out.


The student will be able to explain that catalase breaks down hydrogen peroxide and causes oxygen bubbles to form on organic matter.



Raw chicken livers


Hydrogen Peroxide

Eye droppers

Small knives

Teacher-created worksheet


Have the students work in pairs to find out what happens when they drop hydrogen peroxide on the outside and inside of a tomato and a potato and to a piece of liver. Have them record their observations on a worksheet.

Explain that catalase is an enzyme found in most living things. When the hydrogen peroxide is dropped onto the ruptured cells of the tomatoes, livers, and potatoes the catalase in the cells causes the hydrogen peroxide to break down and oxygen bubbles that are formed.

Discuss why the hydrogen peroxide did not foam when it was applied to the unbroken skin of the tomato and potato (the catalase was still contained inside unbroken cells).


Students can experiment with other organic and non-organic materials to see which have the strongest reactions and which have none at all. This lesson is a quick and easy introduction to enzymes. Encourage your students to have fun with it and to try using other organic materials.