Rock Candy

Kitchen Chemistry: Rock Candy

for School-Aged Children

Materials

• Clean 1 quart glass jar with wide mouth
• Kite string
• Paper clip
• Pencil
• Sugar
• Boiling water

Directions

1. Slowly pour the boiling water into the jar while stirring with a long-handled spoon until all the sugar is dissolved.
2. Begin filling the jar with sugar, 1 tsp at a time, while stirring. Keep adding sugar until the sugar no longer dissolves and begins accumulating at the bottom in a small pile.
   
3. Tie the paper clip to one end of the string and measure the height of the jar plus a few inches.
4. Cut the string and tie the cut end to the pencil.
5. Place the pencil across the mouth of the jar and roll the string around the pencil until the paper clip is just above the bottom of the jar.
6. Place the jar on the kitchen window ledge.
7. Rock candy crystals will grow on the string.
8. The longer the string is in the jar, the larger the crystals will grow.
9. From time to time, break up crystal formation on the jar and on the surface.

Note: Crystals form by precipitation from a hot solution that cools slowly or by evaporation of a liquid. Mineral crystals can also form in these two ways.

**For extra fun, add some food coloring and/or flavoring!