This is not an experiment—because you can eat the results. This is a cooking project which shows how science is part of our lives—even candy! Sugar is a solid. Each little grain or crystal of sugar is made up of lots of individual sugar molecules. The molecules are arranged in a very orderly fashion that gives sugar its shape. Rock candy is made of sugar crystals. The crystals grow bigger than the ones you find in a packet of sugar or the sugar you buy to make cookies. They’re easy to grow—just give it a try! Caution: The sugar/water solution is extremely hot. Please take care when mixing and pouring it.

Remember—you’re going to eat the results—don’t use anything that you wouldn’t use for food preparation)
3 cups sugar
1 cup water
Heavy saucepan
Clean jars or tall glasses
Clean string, straw or popsicle stick

1) Get your crystal growing apparatus ready. You need to suspend your string into the container without it touching the sides or bottom. If you are using a string, you can tie it to a pencil and then lay the pencil across the top of the jar like shown in this image.

Wet your string and dip it into sugar so that a few crystals cling to the string. This will give your candy a place to start growing.

2) Put three cups of sugar in the pan and add 1 cup of water. It will seem like there is too much sugar/not enough water, but it will be ok! Put the pan on the stove and heat the sugar/water solution. Stir it gently. As the solution heats up, more and more sugar will dissolve. The solution will look cloudy. You want to heat it until the solution turns clear and starts to bubble. Be Very Careful—the solution is very hot. Let it cool for 5-10 minutes before proceeding.

3) Pour the solution into the jars. Be sure the string is not touching the sides or bottom. Growing crystals takes time because the crystals grow as the water evaporates. Cover the top with a paper towel or coffee filter to prevent dust from getting into the jar. Put the jar some place where it won’t be disturbed.

4) Check on your crystals every day. If a crust of crystals forms across the top of the jar, just remove it with a fork or spoon so water can continue to evaporate. If crystals form on the sides/bottom of the jar, pour the solution into a clean jar and place the string into the clean jar.

5) When your candy is big enough, you can take it out and eat it. If you want to save it, just let it dry and then store it in a closed container. It won’t spoil, but if you leave it out, it may attract bugs! Enjoy!