My older son is 12 and loves to do experiments, so we thought it would be fun to make some rock candy. This would also be a great thing to do with the kids while they are off for the holiday.
Materials
- Wooden stick--I used a skewer you can buy at any grocery store
- Clothes pin
- 1 cup water
- Tall Cup
- Sugar
- Saran Wrap
- Food coloring if you would like
- Start by bringing one cup of water to a boil.
- Stir in 2 – 3 cups of sugar ½ cup at a time until the sugar is completely dissolved.
- This takes some patience. It takes time and you have to keep stirring.
- Once all of the sugar is dissolved, remove the pot from the burner and let the sugar water cool for 20 min.
- Pour the mixture into a tall cup.
- I placed a piece of Saran Wrap over the top of it really tight, so that it would hold the clothes pin up.
- Poke a hole in the Saran Wrap with the skewer.
- The skewer cannot touch the bottom or sides of the of the glass. Attached the clothes pin to the skewer so that the clothes pin will rest on the Saran Wrap and hold the skewer off the bottom of the glass.
Pro Tip – Dip half of the skewer in the sugar water mixture and then roll it in sugar to jump start the crystal growth. I did it and it worked really well. Allow the skewer to cool completely so the sugar will stay on when you put it in the glass.
Now you just have to let the sugar water cool and put it somewhere it will not be disturbed. Wait for 3 – 7 days and see what happens.
We waited for 3 days because my son could not wait any longer and it turned out quite well. It looks like real rock candy you buy at the store. We put blue food coloring in the mixture and that is why it is blue. You have to use a lot for it to be really colorful.
Have fun !
The Science: Sugar is a solid that has a crystalline structure. If you were to look at your kitchen sugar under a microscope, they would look like little bricks with slanted sides. The granulated sugar in the kitchen has very small crystals, but they can be allowed to grow quite large. Rock candy is made when we give sugar the right conditions to keep growing large crystals.
Trouble shooting: If you find crystals growing on the glass container, those crystals will continue to draw more sugar from the solution. To assure that your rock candy gets most of the sugar, you can transfer the sugar solution into a new glass and set up your skewer again.
