One of our readers, Heike Kubash recently pointed me toward a web site with instructions on how to make "magic crystal trees," something I remember from my boyhood. I remember seeing kits for these kinds of projects where you would place rocks or pieces of wood in a bowl, cover them with a special solution, and gradually a layer of frost-like crystals would cover them.
Over at http://www.stevespanglerscience.com/, you can find a project for making magic crystal trees, but using ingredients from around the house or the supermarket. In keeping with the season, the "trees" are made of cardboard, cut in holiday conifer forms. The fluid soaks through the cardboard and as the solvent evaporates, crystals of table salt and Mrs. Stewart's Bluing precipitate on the cardboard creating the effect of snow or frost.
It's a fun project to do with the young ones over the holidays. For the full instructions for the project, click here.