How to Make Rock Candy

Kids love sugar, as every former or current parent knows. They’d consume pounds at a time if they could, and anything with sugar is almost guaranteed to be a hit. So what could be cooler for a kid to watch than these beloved sugar crystals actually growing? Better yet, what if they could even color them however they want… say, blue? (They don’t think it’s gross!)

Making your own sugar crystals is easy enough that any kid can do it if you give them these instructions. If they’re younger, you might want to supervise them while boiling the water, or do that step for them.

Time required: A few days to a week.

School links: Chemistry and nutrition.

What you’ll need:
-A glass container to grow the sugar in;
-A string longer than the height of the container (rough twine or yarn work well, but nylon doesn’t work well);
-A pencil, knife, Popsicle stick, or another flat object that will stay in place on top of the container;
-Food coloring (optional but fun!)

1. Set the container down, and tie the string onto the pencil. Lay the pencil on top of the container and make sure that the string is long enough, but will not touch the bottom of the container. If you’re determined to get a straight string of rock candy, tie a clean paper clip (boil it in the next step if you’re worried) to the end of the string.

2. Boil enough water to fill the container in a kettle, on the stove, or in the microwave.

3. Begin to stir the sugar in, one teaspoon at a time. Make sure you stir thoroughly after each teaspoon so that all the sugar dissolves. The hotter the water, the more sugar you will be able to add, but don’t put in too much. Once it cools, any sugar left over will drift down to the bottom and become a nuisance later.

4. (Optional) Stir in a few drops of food coloring (not too many – a little goes a long way!) if you want.

5. Carefully pour the water into the container to fill it almost all the way full. If you have some sugar at the bottom that didn’t dissolve, try not to pour it into the container. (Note: If you have younger kids or they are clumsy, be careful that they don’t get burned from the steam or spill water on themselves.)

6. Place the pencil on top of the container so that the string is submerged in the sugary water.

7. Put the jar on a windowsill, desk or ledge where it will not be disturbed or tip over. The more it is disturbed, the longer it will take to form crystals. You can carefully drape a small dishcloth over the container if you don’t want dust getting into it.

8. After about a day, you should begin to see the crystals grow. Remind your kids to be patient and not to touch the jar, or the crystals won’t grow!

9. Leave the jar there as long as you want; the longer you leave it, the bigger the crystals will become.

10. Once you’re ready to remove the string, just pull it out and let it dry.

If you had trouble with this, and crystals didn’t form, make sure the jar is the right temperature. You can also try adding the sugar while the water is boiling, letting it slowly cool down, and then pouring the solution into the jar. Let your kids experiment and write the results of their experiments in their science notebooks.

Enjoy the expression on your child’s face when he sees that he made his own rock candy!