Whether it’s for a science project or just for fun, making rock candy on a stick is a project that provides not only a lesson on how crystals grow, but also the pleasure of a great treat for kids. Creating rock candy on a stick is not a quick project, because it takes a week or more for the sugar crystals to grow; so plan to set aside a few minutes each day to view the process and discuss what is happening. At the end of the project, spend some time examining the crystals and then enjoy your sugary treat.
How to Make Rock Candy on a Stick
Place the sugar, corn syrup, and water in a pot and mix with a wooden spoon. A heavy-duty aluminum pot works best, because it will conduct the heat evenly.
Cook the mixture until the temperature reaches 300 degrees; use a candy thermometer to determine the exact temperature. Stir the mixture constantly with a wooden spoon to avoid burning.
Pour the sugar solution into the glass jar and cover with the Styrofoam.
Push the skewers through the Styrofoam until they are about ¼ inch from the bottom of the jar. Leave at least 1½ inches between skewers to allow for the sugar crystals to grow.
Set the jar aside where it will remain untouched but can be viewed. After about a week, you should have your rock candy on a stick ready to remove.
Rinse each piece under cold water and set it on a piece of wax paper to dry.
Make your candy stick even more interesting by adding a few drops of cinnamon or clove oil to your mixture before heating. You can also add a few drops of food coloring to make your rock candy stick even more inviting.
Make sure the jar is clean, as any contaminants may prevent sugar crystals from forming. Don’t pour the hot mixture into a cold jar, because the sudden temperature change may cause the glass to crack or shatter.