Melted Crayon Pumpkin STEAM Activity

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Fall is finally here, and the boys and I wanted to start decorating for Halloween and fall. While we could do the traditional carving of a pumpkin, I’m fairly certain knives and kids are not a good idea. Also, I had an unfortunate pumpkin carving incident in middle school, so I’m a little averse to the activity. We recently had fun using crayons to rock paint, and I thought it would also be fun to make a melted crayon pumpkin!

A fun melted crayon pumpkin STEAM activity for kids all ages! Use melted crayons to decorate your pumpkin this fall.

Melted Crayon Pumpkin STEAM Activity

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Heating a pumpkin hot enough to melt crayons is a little tricky. Not a high enough temperature, and the crayons will not melt. Too high a temperature for too long, and the pumpkin will soften, making it impossible to color.

First I checked a few recipes for cooking a pumpkin, and the recommended temperature for a pumpkin was 350F for 45 minutes.

Next I checked a previous experiment where we melted different colors of crayons, and found their melting points. From our experiment, we learned that all of the colors completely melt when placed in an oven set at 250F for 11 minutes.

With the previous two pieces of information, we knew the surface of the pumpkin needed to reach a temperature of 250F for the crayons to melt while we colored with them. From there, I was able to come up with a simple STEM activity for the boys!

Melted Crayon Pumpkin STEAM Activity Instructions


STEP 1: Preheat oven to 350F.

STEP 2: Place pumpkin on baking sheet, and place it in oven for 15 minutes.

STEP 3: Carefully take the baking sheet out of the oven, and place the pumpkin on a paper plate.


STEP 5: Once the pumpkin is colored, leave it alone until the crayon completely dries.

Enjoy your new pumpkin decoration!

To color more than one pumpkin at a time, you can repeat the step above, with no changes.

My boys had a lot of fun coloring their pumpkins, and even asked to make more! I will have to pick up more pumpkins the next time I find them for $1 each.

Here’s how our pumpkins turned out!

Melted crayon pumpkin #1.
Melted crayon pumpkin #2.
Melted crayon pumpkin #3.

Where is the science?

Our fun melted crayon pumpkin activity exposes kids to two different science concepts:

  1. Energy Transfer
    Placing the pumpkin in the oven adds heat energy to the pumpkin. When the crayon touches the surface of the pumpkin, heat energy transfers from the pumpkin to the crayon. The heat energy in the crayon makes the molecules of the crayons move so fast that molecular bonds are broken, forming molten crayon.
  2. Phase Changes
    While decorating the pumpkins, my boys played with two different phases of a crayon: solid and liquid phases. When the crayons melted while they colored, they were witnessing the phase change of a crayon from a solid to a liquid.

I love this STEAM activity because it is easy for all my boys to do it together. With a 6 year difference in ages, it is challenging to find activities all three of them will enjoy. But this simple melted crayon pumpkin STEAM activity was perfect for all three of them!

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