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How to Make Easy Iodine Crystals

Growing crystals can be a fun, educational experiment for both children and adults. Teachers can use this activity to help show students how crystals form in the earth, and parents can use it to help their children grow a virtually maintenance-free "crystal garden." Either way, the results are pretty and worth maintaining. Many use sugar, alum or salt as a crystals-growing medium and simply dissolve them in water. Using an iodine solution, however, makes the crystals grow faster and turns them a pretty dark indigo or golden yellow color. Iodine crystals can also continue growing for longer than crystals made in simple water.

Things You'll Need

Water
Ammonia
Iodine
Salt
Disposable spoon
Cork pieces
Large, shallow plastic dish

Instructions

- 1
  Mix about 1/4 cup each of water and ammonia in a shallow plastic dish. Stir them carefully with a disposable spoon and fill the bottom of the container with broken up cork pieces. The cork will absorb the solution and provide a foundation for your crystals.
- 2
  Drip iodine over the cork just enough so that you can see the color on the cork. About four drops per piece should do it. Let the cork soak for about 10 minutes.
- 3
  Sprinkle liberal pinches of non-iodized salt over the cork pieces. You should be able to see the salt sitting on top of the cork, but still be able to easily see the cork. Place the dish in a warm, dry space for 24 hours.
- 4
  Check on the cork. Small salt crystals the color of the iodine should be beginning to form. If the ammonia and water solution is completely gone, mix some more with about 20 drops of iodine and pour it into the bottom of the dish, being careful not to get any on the top of the cork.
- 5
  Keep refilling the plastic dish as necessary. The crystals will continue to grow as long as you continue feeding them.

Rocks & Minerals