Experiments for Kids: Heat and Release of Gas

Amy Hawthorne

by Amy Hawthorne

3rd November 2014


You have found the first in a four-part series based around experiments that kids can safely get involved with. We hope these exciting chemical reactions will encourage children to learn about chemistry and discover how exciting science can be!

Experiment 1: Heat and Release of Gas

Chemical reactions occur when two or more elements or compounds (called reagents) interact with each other to form new products. Bonds are broken and new bonds are created for a chemical reaction to take place.

Chemical reactions are usually accompanied by a visible process that we can see and measure. In the first experiment for kids, we see two changes:

  • We see bubbles which signify the production of gas.
  • Heat is also produced in this experiment, making this an exothermic chemical reaction.

In this chemical reaction, we’re looking at the release of oxygen from hydrogen peroxide, by adding yeast. The yeast contains an enzyme called catalase which promotes the following reaction:

2 H2O2 -> 2H2O + O2


  • 1 teaspoon dry yeast (you can find this in the baking aisle in the supermarket, usually near flour)
  • ½ cup of hydrogen peroxide (present in various products including antiseptic, mouthwash, contact lenses solution and bleaching hair products – use the highest concentration possible)
  • Thermometer
  • Something to stir with
  • Clear glass or plastic container


  1. Simply add the dry yeast to the hydrogen peroxide and watch as the bubbles begin to form and bubble away.
  2. Once the reaction has started, oxygen gas will be released and you should also be able to feel the container get a little warmer. If you want to be accurate, measure the temperature before and after the reaction to see how it changed.
  3. To test the gas released, ask an adult to light up a match, put it out again and place it on top of the container as the gas is released. If it gets in contact with oxygen, the match should light up again. (As if by magic!)

If the bubbles aren’t very clear, add some washing-up liquid to the mixture to produce foam. This is caused by the oxygen being released as hydrogen peroxide is decomposed.

Always wear the correct protective clothing when carrying out any experiment. It may be a good idea to place the container in the sink or a place that’s easy to clean!

See More from ‘Chemical Reactions for Kids’

Experiment 2: Green Pennies and Copper-plated Nails
Experiment 3: Splitting Water (Electrolysis)
Experiment 4: What Factors Affect a Reaction?


All content published on the ReAgent.ie blog is for information only. The blog, its authors, and affiliates cannot be held responsible for any accident, injury or damage caused in part or directly from using the information provided. Additionally, we do not recommend using any chemical without reading the Material Safety Data Sheet (MSDS), which can be obtained from the manufacturer. You should also follow any safety advice and precautions listed on the product label. If you have health and safety related questions, visit HSE.gov.uk.

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