Homeschool Science: Rock Candy Experiment

homeschool science rock candy experiment

What’s better than a science experiment that you can learn from and then enjoy the tasty results afterwards? In this experiment, you make your own rock candy, watching as the rock crystals grow each day. Plus, there’s an awful lot of chemistry behind candy making which serves as a great science lesson. Here’s how it works:

What you need:

  • 2 or 3 cups of sugar
  • 1 cup of water
  • Food coloring (and if you’d like, candy flavoring)
  • Skewers, 1 per candy
  • A large jar or glass, 1 per candy
  • A large saucepan
  • Clothespins

What to do:

  • Pour equal parts of water and sugar into a saucepan. Heat until all of the sugar has dissolved.
  • Add more sugar in small amounts until it no longer dissolves in the water. It will look a bit cloudy when it’s done. This is called a saturated sugar solution, which means that at this temperature no more sugar can dissolve.
  • If you’re using candy flavoring, pour it in. Then, continue to heat your sugar solution until it begins to simmer.
  • Remove the sugar solution from the heat. While it cools, work on your jars.
  • Cut your skewers to a size relative to your glasses or jars. You want there to be some room at the bottom of the jar, as well as enough skewer to hold onto when you eat the candy.
  • Dip the skewers in water and then roll in sugar. Let these dry.
  • When your sugar solution has cooled down, pour it into your jars. If you’re using food coloring, add that in too.
  • Once your sugar-coated skewers are completely dry, place them securely in clothespins. The clothespins will rest horizontally on the mouth of the jar to keep the skewers from falling in. Make sure the skewers don’t touch the bottom or sides of the jar.
  • And you’re done! Over the next few days, your rock candy will grow. It needs the sugar on the skewers to attach to. By allowing your saturated sugar solution to cool, you created a supersaturated solution. A supersaturated solution is unstable – essentially there is too much sugar dissolved so some of the sugar will return to solid form and attach to the skewers.
  • Once your rock candy has grown to a size you like, remove your skewers from the jars and let them dry. Then, enjoy your tasty treat!

Enjoy and don’t forget to sign up for SD Accelerate’s free trial!