Pamela Follett/Demand Media

A perennial favorite in both science labs and home kitchens, a rock candy experiment offers a fascinating glimpse into the world of sugar crystal formation. The classic process involves mixing sugar and water in a jar, then dangling a string into it. After about a week, it results in a sugary hard candy treat. By tweaking the process slightly, you can reduce the time it takes to deliver your sweet reward.

Pamela Follett/Demand Media

Cut string into 6-inch lengths and tie one or two to each pencil. The fewer strings you use per pencil, the more quickly the rock candy forms.

Pamela Follett/Demand Media

Boil 1 cup of water for every 2 to 4 cups of sugar. Use more sugar for faster crystal formation. Increase the amount of water and sugar at the same ratio to make more candy.

Pamela Follett/Demand Media

Add the sugar 1 cup at a time.

Pamela Follett/Demand Media

Stir vigorously until the sugar dissolves. High heat and vigorous stirring encourage the large crystals needed for faster rock candy formation.

Pamela Follett/Demand Media

Drizzle in the optional few drops of food coloring now. Stir it until it combines with the sugar syrup.

Pamela Follett/Demand Media

Take the pot off the stove and let the syrup cool for about 5 minutes.

Pamela Follett/Demand Media

Set out containers or jars just slightly deeper than the length of string. The more containers you use, the more room you give the rock candy to form quickly on the strings.

Pamela Follett/Demand Media

Pour syrup through a strainer into the first jar to about one-third or halfway full. Strain to catch any clumps in the syrup that could attract crystals to the bottom of the bowl as they settle, rather than on the candy string.

Pamela Follett/Demand Media

Wet the strings and drag them through granulated sugar spread on a plate. This step jump-starts the crystallization.

Pamela Follett/Demand Media

Lay each pencil across the width of the container, so that the strings dangle into it. The strings should not touch the bottom of the jar or each other.

Pamela Follett/Demand Media

Cover each container loosely with a paper towel. Allow good air circulation for swift crystal formation, which requires evaporation.

Pamela Follett/Demand Media

Set the bowls in the driest part of your house. The less humidity, the more quickly the water evaporates and the rock candy grows.

Pamela Follett/Demand Media

Knock down any sugary "skin" that forms along the top of the container. This hardened syrup, once reintroduced into the bowl, speeds the formation of the crystals on the strings themselves.

Pamela Follett/Demand Media

Pull the strings from the pencils once the candy reaches a size you like. Snip the string on both ends for a more stick-like presentation.

Tip

For a more elegant presentation, use wooden skewers instead of string. Alternatively, select clean, decorative ribbons to form the base of candy-coated jewelery.

Warning

Wear long sleeves when you boil the sugary syrup, and use a potholder to move the pot and pour from it. Even after its 5-minute cooling period, the sugary syrup remains hot.

About the Author

Ellen Douglas

Ellen Douglas has written on food, gardening, education and the arts since 1992. Douglas has worked as a staff reporter for the Lakeville Journal newspaper group. Previously, she served as a communication specialist in the nonprofit field. She received her Bachelor of Arts from the University of Connecticut.