Awhile back, my son and I decided to recycle some of his old crayons around Valentine’s Day. We tried melting some broken red, white, and pink crayons, and melting them all at the same time. But while we waited for them to melt, we had some unexpected results, which left us wondering…How does the crayon color affect the melting temperature and how long it will take to fully melt the crayon. We came up with our own rainbow science experiment to explore the melting point of all the colors of the rainbow!
Rainbow Crayon – a Crayon Melting Point Experiment
** This post also contains affiliate links and I will be compensated if you make a purchase after clicking on my links. Please see disclosure for more information**
- Cylinder shaped silicone ice tray
- 4 crayons of each color: Red, Orange, Yellow, Green, Blue, Indigo, and Purple
- Coffee grinder
- Baking sheet
- Oven thermometer (the one that came with your oven)
Finding the Melting Point for Each Color of the Rainbow
Step 1: Preheat your oven to 250°F.
Step 2: Starting with RED, peel the paper off the crayons.
Step 3: Break the crayons into pieces and place them into the coffee grinder. Grind the crayons until there are no big pieces of crayon.
Step 4: Pour all the ground up crayon into the silicone ice tray, and place the ice tray on a baking sheet covered in foil.
Step 5: Carefully place your oven thermometer into the ground up crayon. You want to make sure the thermometer stays in the melting crayon to get a true temperature. Place the baking sheet into the oven, and connect your thermometer to the oven.
Step 6: Using the table below, mark down the temperature of the crayon as soon as you place it in the oven. Every minute, record the temperature of the crayon. Stop taking temperatures once the crayon is completely melted.
Step 7: Once the crayon is melted, carefully take the baking sheet out of the oven. Allow the crayon to completely solidify.
Step 8: Carefully remove the crayon from the ice tray.
Step 9: Repeat steps 1 through 8 for all the other colors.
Looking at all the temperatures, do you see a trend?
Here is a graph of our temperature results:
My son and I learned two things from the graph that helped us make a rainbow crayon:
- All the crayons are completely melted in 11 minutes.
- The melting point of each color decrease as you go down the order of rainbow, with the exception of green. For example, red melts at the highest temperature, then yellow, then orange, and so on.
3 Engineering Activities!
Explore the fields of Mechanical, Chemical, and Electrical Engineers with this 3 day email course about engineers!
Make a Rainbow Crayon
Step 1: Measure the length of one of the crayons colors you just made, and divide that number by 7. For my crayon the number came out to be 3/4″.
Step 2: Cut each crayon into 7 even length sections.
Step 3: Place one section of each color into the ice tray in the order of the rainbow.
Step 4: Place the ice tray back onto the baking sheet, and place the baking sheet into the preheated oven.
Step 5: Set the timer for 11 minutes. When the timer goes off, carefully remove the baking sheet from the oven. Be careful not to tilt the ice tray so the colors don’t run together. Wait for the crayon to solidify, then carefully remove it from the ice tray. Now you have a rainbow crayon!
Interested in other Science Experiments? Here are some of my others ones!
The Science Behind Melting Crayons
Making Snow at Home when its Hot Outside
Tensile Strength Experiment: Find the Strongest Spider Web!
Law of Inertia Experiment using a Fidget Spinner!
Center of Mass Fidget Spinner Experiment
Physics for kids with Beyblades
Make an American Flag Using Water Science Experiments
Learn about Forces at the Splash Park!
Exploring Energy for Kids: How Are Height and Distance Related?