Radiant Energy To Thermal Energy Experiment

Radiant Energy To Thermal Energy Experiment

Simple Experiment for Converting Radiant Energy into Thermal Energy

I thought I would share a really simple but very cool experiment to demonstrate Radiant Energy being converted into Thermal Energy.

First, let’s define:

Radiant Energy = 1. energy transmitted in wave motion, especially electromagnetic wave motion. 2. Light

Thermal Energy = energy in the form of heat

Just a Note: You will be making fire so parental supervision is a must and this experiment is only appropriate for older students.


For this experiment you will need:

  • a pie plate or cake pan
  • a small piece of white paper
  • a magnifying glass
  • a glass of water

Your goal is to concentrate the radiant energy coming from the sun with the magnifying glass effectively converting the radiant energy into thermal energy. If you can heat the paper until it actually burns then you have successfully converted it into thermal energy.

Here is how it went for us.

We ripped off a small piece of paper and found a place where we had direct sunlight. We then placed the scrap in the pan and tried to focus the light with the magnifying glass into a tiny circle on the paper.


Once we had the light focused into a small dot on the paper it took less than a minute for the paper to begin to burn.


T loved this experiment. Anything that gets us outside he likes but he loves hands-on experiments and more importantly, he remembers the lessons so much more than if we had read about the experiment alone and not seen it in real life.  So, Science was a success today!

Option:  You can also use a piece of black paper and show them that it lights even faster. This demonstrates that black paper absorbs more light than white paper which reflects the most light.

If you are interested, you may check out this lesson from PBSLearningMedia which offers several great lessons on Thermal Energy Transfer. We use a lot of material from PBSLearningMedia in our homeschool.

Thermal Energy Transfer

Average rating: 5 stars – 2 ratings Explore the three methods of thermal energy transfer: conduction, convection, and radiation, in this interactive from WGBH, through animations and real-life examples in Earth and space science, physical science, life science, and technology.

Finally, we love to hear from you. Have you tried this with your children yet? Do you have a great resource you would like to share? Please feel free to comment below.

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