Heat and Colors Experiment

(Physics for ages 5+)

Have you ever noticed that you get hotter when you wear dark-colored clothes on a sunny day compared to when you wear light-colored clothes?



White canvas or poster board

Pack of crayons (the more the better)



Easel or something to prop up the board

Old towel or cookie sheet

Sunny day

Adult supervision (Adult Supervision at all times please)



  1. First, remove the paper wrapping from your crayons.
  2. Next, glue each crayon side-by-side along the edge of the canvas or board. In the video above, the crayons are arranged from dark-colored to light-colored. This is a great arrangement to compare different color spectrums, but feel free to get creative if you would like to arrange them differently.
  3. Find a nice sunny spot to set-up your canvas. This activity works best on a hot day with few clouds in the sky. Try to have it all set up before lunch to give the crayons as much time in the sun as possible.
  4. Set up your easel or another object that can be used to prop the board up (like a log or garden gnome). Place an old towel or cookie sheet underneath the board to collect any wax that may drip all the way down. The board should be set up at a sloped angle so the wax slowly drips down as it melts. It should also be facing the sun.
  5. Set the thermometer in the sun next to the board.
  6. Leave the board undisturbed in the sun for as long as possible or until all of the crayons have melted. Be sure to check on it every hour or so to see what is happening and write down your observations. Are the darker crayons melting faster? How hot is it? How long does it take for the different colors to absorb the heat and melt down the board?



We are able to identify different colors because they have different wavelengths that absorb or reflect light differently. Very dark colors, like black, blue, and maroon absorb lots of light, while lighter colors (green, yellow, and red) absorb less light.

This is why if you wear dark colors on a hot, sunny day, you will feel hotter than if you wear light colors. However, if it is a cold day, you might want to wear dark colors so you absorb more light from the sun and stay warmer.