Science Buddies: "Ask an Expert"

My teacher won’t let me do the “Crazy Crystal Creations” project unless I have a good purpose to it. Are there any good ideas to how making sugar crystals can relate and help in the real world?

This experiment lets you explore the process of recrystallization, which is a technique used widely by chemists. Its purpose is to purify solids.

For example, say you have a solid that is made up of two different substances and you want to isolate the one with the lower solubility. You would do this by dissolving as much of the solid into a solvent as possible at boiling point (this is called supersaturation). Once the temperature decreases, solubility decreases, and the less soluble substance precipitates from the solution in the form of crystals. The other substance remains dissolved.

You can see how being able to separate substances from one other is useful in chemistry. Pure substances are hard to find the real world, so chemists use lab techniques like this instead.

-Karen Zhang