MAKING A CRYSTAL GARDEN                     

Contributed by Best Science Supplies

First, a little about crystals.                                     
Crystals are solids that are formed by  regular and repeated patterns of molecules that are connected together. In some solid materials,  the atoms and molecules, their building blocks can be arranged at random or vary differently throughout the material. In crystals, a collection of atoms called the "unit cell" is repeated in exactly the same pattern over and over throughout the entire material.
Because of this repetitive nature, crystals can take on strange and interesting  forms. When we grow crystals we are separating all the building block atoms and molecules into individual units in water and letting them fall naturally into their appropriate place in the repetitive structure as the water evaporates.
Crystals start growing by a process called "nucleation". Nucleation can either start with the molecules themselves (we'll call this unassisted nucleation), or with the help of some solid matter already in the solution (we'll call this assisted nucleation).

Here are some fun and interesting experiments you might enjoy:

Crystal Garden #1
You will need:
Ammonia - 2 tbsp.
Water - 2 tbsp.
Iodine - 10 drops
Glass pan
Food coloring - 10 drops
Small lumps of coal or corks
Salt - 2 tbsp.
Mercurochrome - 10 drops

Arrange the coal or corks along the bottom of the glass dish.
In another container mix 2 tablespoons of salt, ammonia, water, and mercurochrome.
Pour this solution over the coal or corks.
Scatter ten drops of mercurochrome, iodine, and food coloring over the top.
A crystal garden will begin to form in several days as the moisture evaporates.
Add more of the solution to increase the size of the crystals. 

Caution:  These crystals are NOT edible.

Crystal Garden #2
You will need:
1 brick
4 tbsp. bluing (available from The Vermont Country Store)
4 tbsp. table salt, no iodine
1 tbsp. ammonia
4 tbsp. water base food coloring
1 bowl or decorative plate

Break brick into chunks and place in bowl.
Mix salt, bluing, water, ammonia and pour over brick pieces.
Drop food coloring here and there on brick pieces.
Let sit at least overnight to several days.
Caution: crystals are very fragile.

Caution:  These crystals are NOT edible.