What if you could grow crystals and then eat them? Rock candy is more than a sweet treat; it’s a hands-on way to see chemistry in action. Crystals form when molecules arrange themselves in repeating patterns. In nature, this is how minerals like quartz or salt grow, sometimes over thousands of years under heat and pressure. With sugar, you can speed up the process in your kitchen.
When you dissolve sugar into hot water, you create what scientists call a super-saturated solution. That means the water is holding more sugar than it normally can. As the solution cools and water evaporates, sugar molecules start to line up and stack together into crystals. The longer you let them grow, the bigger and more beautiful they become.
NOW TRY IT: GROW YOUR OWN ROCK CANDY
What You’ll Need
• 2–3 cups sugar
• 1 cup water
• A clean glass jar
• Wooden skewer or string
• Clothespin or tape
• Optional: food coloring or flavor extract
STEP 1: MAKE A SUGAR SOLUTION
Ask an adult to help heat the water until hot but not boiling. Slowly stir in sugar until no more dissolves. That’s your supersaturated solution!
STEP 2: PREPARE YOUR STICK
Dip a skewer in the sugar solution, roll it in dry sugar, and let it dry. This “seed layer” helps crystals stick.
STEP 3: SET UP YOUR JAR
Pour the sugar solution into the glass jar. Place the skewer inside, making sure it doesn’t touch the bottom or sides. Use a clothespin across the jar’s top to hold it steady.
STEP 4: GROW YOUR CRYSTALS
Set the jar aside at room temperature. Watch over 5–7 days as crystals grow. The longer you wait, the larger they’ll be.
STEP 5: ENJOY!
Once your crystals are big enough, (or you can’t wait any longer), try them! You don’t always get to eat your science experiments, so we hope you enjoy this one!