Originally posted here
Science Experiment: Crayon Making
You will need: crayon bits, tin cans or bowls for melting, silicone mold
Point of Experiment: Wax can change from a solid to a liquid when heated. It will become solid again when it cools. Discuss forms: solid, liquid, gas. What other things change form when heated? Do they go back to their original form?
First, the kids removed paper from broken crayons. Then we sorted them into bowls by colors. Since my mold had six spots, we made six piles:
1) black, white, and grays
2) blues and purples
3) reds, pinks, and dark oranges
4) remaining oranges and yellows
From there, I took 2 metal bowls from my kitchen stash. The larger bowl was filled with water and placed over medium high heat. The broken crayons were placed in the smaller bowl. When the water in the large bowl was boiling, the small bowl was placed inside. As the wax melted, we stirred the wax mixture.
When the wax was completely liquid, I poured the wax into the mold (which were hearts). It took about half an hour for the wax to reharden, then the kids popped them out and voila! Six, brand new crayons and a science experiment complete!