Yes, You Can Grow Crystals without Heat by an Evaporation Method
Crystals grown by the evaporation method are generally larger and better formed. This method is slower but the results are worth the wait. Basically a solution is made with water and a crystalline solid, such as copper sulfate or potassium aluminum sulfate (alum). Copper sulfate and alum crystals grow best with the evaporation method.
Getting Started
1. Use a very clean container and work in as dust free environment as possible.
2. Make a saturated solution using distilled water as the solvent.
A saturated solution is made by adding a solute until no more will dissolve.
Use the Wikapedia Solubility Table to decide the mass of solute that will dissolve in 100 mL of water atambient (room) temperature. http://en.wikipedia.org/wiki/Solubility_table
- How to make a saturated copper sulfate solution.
At room temperature, about 32 g of copper sulfate will dissolve in 100 ml of water. Dissolve copper sulfate in distilled water until this solute stops dissolving. At this point there will be crystals of copper sulfate that settle to the bottom of the container and no amount of stirring will cause these crystals to dissolve.
Caution: Adult supervision is required when handling copper sulfate because it is toxic. Copper sulfate is used to kill roots in drains. Do use special precautions when working with this toxic chemical. Toxic means poisonous; Wear gloves, an apron, and goggles. Alum is not toxic. But you do not want to get it in your eyes. So wear goggles and an apron is always suggested. - Pour the saturated solution through filter paper to remove any undissolved solute. The diagram shows a funnel lined with filter paper. You can use a coffee filter or even a paper towel instead of filter paper. Keep the filtrate (liquid that passes through the filter). This is the saturated solution.The solid copper sulfate left in the filter can be dried and saved for future use.
- How to make a saturated of alum (hydrated potassium aluminium sulfate with the formula KAl(SO 4)₂·12H 2O.)
At room temperature dissolve about 10 grams of alum in 100 ml of water.
3. Cover the container with piece of paper and insert a craft stem through the center of the paper and down into the solution.
You want the solvent (water) to evaporate slowly at ambient temperature (room temperature). As the water evaporates the solution becomes more concentrated, meaning the ratio of solute to solvent increases. You now have a supersaturated solution. This means that there is more solute dissolved in the water than normal at ambient temperature (room temperature).
Supersaturated solution are unstable, which means the excess solute dissolved in the water tends to precipitate (fall out of solution). Some crystals that participate attach to the craft stem. These are called seed crystals, which provides a surface for other precipitating crystals to attach to. The size of the crystals continues to grow as more solute falls out of solution and sticks to the crystals.