On what material do sugar crystals grow best?

Will sugar crystals grow faster in tap water, distilled water or bottled water?

• This is a science fair project to see which will grow faster. I also need to know how to do this project.

• Answer:

  It makes little difference. In each case, dissolve an accurately measured amount of sugar in an accurately measured amount of water, and pour the solution into a Petri dish. Crystallization will probably be seen first in the tap water, as it might have condensation nuclei on which crystal deposition can take place.