Any activity that involves learning and eating a yummy treat is likely to be a hit with the kiddos. Although making rock candy takes patience, the sweet confection is worth the wait. When explaining the process to your kids, keep it simple, but do offer a few details about how and why the sugar transforms into hard crystals to make the candy-making something of a learning experience.
Prepare a 12-inch length of string for the rock candy several hours or even the day before you plan to introduce your kids to making rock candy. Mix the 1/2 teaspoon of sugar and 1 teaspoon of water together, and then coat about 3 inches of one end of the string with the sugar mixture. Stretch out the string and set it aside somewhere to dry.
Show your little one a prepared chunk of rock candy and let her hold it before you begin making your own. Encourage your child to feel it, touch it and even lick it if she wants, so she gets an idea of what rock candy is. Tell her, “Rock candy is one of the first kinds of candy that people learned how to make. A long time ago, people even used rock candy to make some kinds of medicine."
Tell your child, “It only takes two ingredients and a little time to make rock candy. If we mix water and sugar together very carefully, we can make it ourselves. Would you like to try?”
Measure 1 cup of water and 3 cups of white sugar. Let your little one help you stir the ingredients together in the saucepan.
Heat the sugar water over medium-high heat, stirring constantly until it boils. This isn’t the time or place for little assistants – make sure you’re handling the heating process by yourself without help to avoid burns. When the mixture boils gently for about 30 seconds, turn off the burner and move the saucepan off the stove.
Pour the hot sugar water into the canning jar. Watch for splashes – this sugar water could be lethal if it spills.
Grab that string you prepared and tie the unsugared end of it around the pencil so that the string is long enough to go beneath the surface of the sugar water -- about 1 inch. Position the string into the jar with the pencil laying horizontal over the top of the opening of the jar. Drape a piece of paper towel over the top of the jar.
Find a safe spot to store the jar to let the rock candy start to grow.
Check the rock candy every day to see how it’s growing. As you check it, seize this opportunity to explain how rock candy works to your little one. You might say, “We mixed up the water and the sugar to make very sweet water and then we made it very hot. The combination of sugar and hot water made the ingredients change as the water started to cool. The other thing that happened was that some of the water started to disappear because we let it sit so long in the jar – we call this 'evaporation.' The cooling and evaporating water made the tiny sugar molecules come out of the water and they attached to the string. The more time that goes by, the more sugar molecules form on the string.”
Let your little one sample the rock candy after a week or 10 days pass -- and you have a sweet little chunk of candy growing on the string.