Sugar Crystals

Introduction to How Crystals Form:

Crystals are defined as solid pieces of small regularly-shapes. These shapes take place because of the atoms and molecules arrange in an orderly, regular pattern. We see this shape because of the arrangement of atoms inside them.

There are seven different types of crystals:

• Cubic,
• Tetragonal,
• Hexagonal,
• Orthorhombic,
• Monoclinic,
• Triclinic, and
• Trigonal.

Here are pictures of the seven different types of crystals (not to scale):

Chemistry Aspects of Crystallizing Formation:

Table sugar is the most common crystal. Many things can be done with sugar, which is why it is a component in many candies.

Sugars (sucrose) are made of simple molecules bonded together. --> 1 glucose and 1 fructose = sucrose.

Through a magnifying glass the atomic nature of sugar can be seen in crystalline form. The sugar molecules arrange themselves in orderly geometric patterns, as seen above in the seven didn't types of crystals.

Here is a diagram of the simple molecule formation:

Heating and Cooling Phases of Sucrose to Begin Crystallization

Adding sucrose to waster dissolves the sugar crystals into the solution, but it isn't dissolving an infinite amount of the sugar, to do this the entire heating and cooling phases would need to occur. The solution right now (sucrose mixed with water) is called saturated.
At different temperatures the saturation point is also different. The higher the temperatures, the more sugar that can be help in the solution. As the water boils more and more water disappears through vapors. It is when the cooking is through and the solution begins to cool that there is more sugar then normally possible. At this point the solution is called supersaturated.
NOTE: The solution we made was brought up to 175 degrees F. and once it reached this temperature it was removed from the heat and stirred back down to 125 degrees F. Once it reached this temperature it was poured into a glass container to cool down to room temperature.
Supersaturation is an unstable state. The sugar molecules will begin to crystallize back to its solid state as the solution is brought back down from 125 degrees F. until it reaches room temperature.
It is here we really see the crystallizing happen. As more water gets out the more crystals form. Once the solution reaches room temp. the solution is covered to speed up the crystallization process.

Here is a diagram of the heating and cooling phases:

For More Information on Sugar Crystallization Visit:

• http://encarta.msn.com/media_461517912_761570052_-1_1/Crystal_Formation.html
• http://www.caosclub.org/totalcaos/members/caosho24.html - a lesson plan!!!
• http://www.baking911.com/candy/101_crystallization.htm
• http://www.exploratorium.edu/cooking/candy/sugar.html
• http://www.madsci.org/posts/archives/mar2000/952398196.Ch.r.html