While rock candy may be a tasty treat, the chemistry behind this candy makes for a great at-home experiment to do with children! Follow these directions to create your very own rock candy. All you’ll need are a few household items to become a chemist without leaving your kitchen! Recommended age range: 5+
- Five cups sugar
- Two cups water
- Two clean 16 oz jars
- Food coloring
- Flavoring extract
- Stirring spoon
- Medium sized pot
- Two bamboo skewers
- Four clothes pins
- Measuring cups
Make a prediction! You’ll come back to this experiment each day for a week to check on your rock candy! What changes do you expect to see on the first day? How about the second day? What do you think your experiment will look like at the end?
Write down or draw your predictions and compare them to what you see during this experiment!
- Cut the skewers to the length of the jars. Wet them with water, leaving 1 ½ inches dry on one end of each skewer. Spoon sugar onto the damp skewers, rotating to coat evenly and then set aside to dry thoroughly.
- Pour two cups of water into a pot. Place the pot on the stove and turn the burner to medium / high heat.
- Slowly begin to pour five cups of sugar into the water and stir continuously until dissolved. Once most of the sugar has been added, the mixture will become thicker and cloudy as the sugar breaks down
- Once the mixture comes to a steady simmer / low boil, add in 2-3 drops of any desired flavoring (orange, pineapple, grape etc.) as well as 2-3 drops of food coloring and wait for the mixture to come to a low boil once more before removing from the heat.
Step 5 & 6:
- Let the rock candy mixture cool down in the pot before pouring it into the two mason jars. Help the process along by placing the jars in the fridge for 20-30 minutes.
- Once the mixture is completely cool, place a dry sugary skewer into the center of the mixture with the 1 ½ inch uncoated end sticking out. Use a clothes pin to secure the skewer in place and rest the edges of the clothes pin along the top of the jar, keeping the skewer in the center of the liquid
- Leave the jars on a counter top with a paper towel draped over the clothes pins and check on your rock candy creations each day for one week. You should notice crystals forming after just one day!
After the experiment, think deeper about the reactions you saw! Ask questions like:
- What did you notice as you observed your experiment each day? What changes did you see?
- Did anything in your experiment surprise you?
- How long did it take to see crystals forming? Keep a log book or photo journal to keep track!
- What would happen if you added more/less sugar to the mixture? Do the experiment again to find out!