How To Make Rock Candy

From: Science Is... by Susan V. Bosak
Materials:
boiling water, sugar, drinking glass, spoon, clean string, clean paper clip, pencil, paper towel, magnifying glass.
Doing It:
1. Fill a drinking glass about a third full with boiling water. Stir the sugar into the water until no more dissolves ( it is super saturated because you've heated it). You can dissolve a lot of sugar in a little water; the ration is about 2 parts sugar to one part water.
2. You should end up with a thick syrup, you may see a few sugar grains floating in the solution.
3. Tie one end of a piece of string to the middle of a pencil and the other end to a clean paper clip.
4. Wet the string and paper clip and brush them through dry sugar so the grains of sugar stick to them.
5. Place the pencil across the rim of the glass so that the paper clip is suspended midway in the solution.
6. Put the glass where it won't be disturbed, cover it loosely with a paper towel or plastic wrap.
7. After several days, crystals will form around the paper clip and string. If the water evaporated slowly, the crystals will be quite large. Use the magnifying glass to examine them. Compare them to grains of sugar. Taste the crystals. Why do you think they call it rock candy?

The Science Behind Rock Candy:
When sugar dissolves in water, the water molecules cause the sugar molecules to break away from each other. Much more sugar dissolves in hot water than in cold water. The solution is 'saturated' with sugar. As the water cools, the large number of sugar molecules are attracted to each other again. They pack close together in a specific pattern. Grains of sugar on a string act as 'crystal seeds', as a starting place for sugar crystals to grow. It is possible to grow sugar crystals but it takes longer.