Growing Crystals

Background:Crystals are generally defined as solid objects that are comprised of a repeating pattern of three dimensional atoms, ions, and molecules.A crystal resembles a geometric form while the external shape of the crystal is smooth and symmetrically arranged, reflecting the internal arrangement of its atoms.

Equipment

To make your own crystals, you'll need a few items.

  • A heat-proof, glass jar (a mason jar is excellent.)
  • A measuring cup
  • About 1 cup of boiling water
  • About 1/2 cup of alumammonium aluminum sulfate - NH4Al(SO4)2.12H20
  • Popsicle stick
  • Cotton string
  • a spoon (for stirring)
  • a seed crystal
  • coffee filter to act as a dust cover

Prepare a Supersaturated Solution

Tie the seed crystal to one end of the string, and the Popsicle stick to the other end. When you place the Popsicle stick across the top of the jar, the string should be just long enough to let the seed crystal hang about ¾ from the top of the jar. Set the string, Popsicle stick, and seed crystal aside until your solution is ready.

1.Boil about one cup of water on the hot plate. Watch the temperature and do not let the water become too hot.

2.Remove the water from heat and add the alum. Add the alum one teaspoonful at a time. Stir until each teaspoon is completely dissolved.Be patient. Eventually, you'll find a small amount of alum will not dissolve and collects at the bottom of the jar. You have reached supersaturation. Once the solution is supersaturated, stop adding alum. If desired we can add a couple drops of food coloring. (Clear crystal’s often look better)

3.Pour the mixture into your container.

4. Let your solution cool for several minutes. If you place the seed crystal into the solution while it is to hot it will dissolve and the experiment will not succeed.

5. Lower the seed crystal and string into the water and rest the Popsicle across the top of the jar. Cover the jar lightly with a coffee filter to keep the dust out.

5.Place the container in location where it will not be disturbed. Crystals will form as the water evaporates.

Tips: The cleaner the jar the better and bigger the crystals will be. If any impurities or dust collects in the solution the crystals will be small and clustered. So take care to clear your jar and keep the dust out.