Making Crystals            

Objective:  Students will create crystals to identify their habits.

Question:  What type of habit do alum crystals have?

Materials: 7ounces of alum, water, heat source, pan, saucer, glass jar, cloth, tissue, wire frame, thread, and a padded container

Procedure:

   1. Dissolve five ounces of alum in a pint of water and heat it (without boiling).  Add more alum until no more will dissolve.  This creates a saturated solution.

   2.  Take the pan off the heat and pour a little liquid into a saucer.  This will provide your seed crystals.  place in a cool cupboard.

   3.  Pour the rest of the solution into a clean glass jar and cover it with a cloth to keep the dust out.

   4.  In a few days, small crystals will appear in the saucer.  leave them until they are 2-3 millimeters across, then pour off the liquid and dry the crystals on a piece of tissue.

   5. Pour your main solution into a clean jar, leaving behind the small crystals that have formed.  Then hang your best crystal in the solution using thread and and a wire frame.  Make sure that all the wire is under the surface.

   6.  Cover the jar again to keep out dust and place it in a safe place.  once the crystal starts to grow examine it. 

   7.  When the crystal stops growing you can dry it on tissue and store it in a padded container.

   8.  Notice the shape or habit of the crystal.  Are they square? What shape are they?  What color are they?  Do other materials create crystals with different habits and colors?

   9.  Use the microscope for further examination.

Record your observations:                                                               

Conclusion:  What can you conclude about the habit of alum crystals?

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