Mini Project #2: Rock Candy

In chemistry class, we made rock candy, also known as crystallized sucrose.

Materials:

Popsicle Stick

String

Lifesaver (to weigh the string down)

Glass Beaker

Pot with Saturated Sugar Water (1 cup water, 3 cups sucrose)

Instructions:

1. Tie your lifesaver onto a string, which should be the length of the glass beaker you are using.
2. The tie the string (and attached lifesaver) to a popsicle stick and place into the glass beaker. The string should hang about 1/2 - 1 inch off the bottom of the beaker and should be placed strategically in the middle, so it avoids touching the sides.



3. Boil a pot full of saturated sugar water.
4. Pour the hot solution into the the glass beaker.
5. Place the beaker in a place where it will be undisturbed. Crystals will form when the liquid cools down after a few days to a week.

* Crystals will not form on nylon string.




Safety Procedures

Use hot mitts to handle the pot full of boiling hot water!

Wear your goggles in case hot water splashes into your eye!

Do not use a wishing weight or anything metal to weigh down your string. This could be potentially toxic if you're going to eat your rock candy.

Scientific Principles
1. Crystallization:
Crystals are formed when a substance arranges itself in repetitive arrays. The supersaturated sugar solution contains more sugar than water. As the solution cools over days, the sugar forms as a precipitate on the string.

2. Evaporation:
Over time, the water molecules from the supersaturated sugar solution leaves the rock candy. The crystals thus grow molecule by molecule.

PHOTOCREDIT TO FIONA CHAN AND MARCIA LEE!