1. By David Braunstein MESA Schools Program Academic Coordinator
How are Crystals Made?
By David Braunstein
MESA Schools Program
Academic Coordinator

2. Crystals MESA Specifications What are crystals?
What materials can be used?
What is the process for making crystals?
What else is needed to be a winner?
Experiment—MAKING IT CLEAR!

3. MESA Specifications
Material to be used is Potassium Alum. AlK(SO4) H2O
Also called Aluminum Potassium Sulfate Dodecahydrate.
Crystal need to be large, clear, well-shaped, and beautiful.
SOLUTION needs to be CLEAN.
You need to WRITE what you do IN a LOGBOOK.

4. MESA Specifications (con’t)
Growing time determined by the students.
Display includes graph
Crystal size (VOLUME) vs. TIME
Take photos of Crystal growth during cycle.
Size may be determined by
Measurement
Displacement
Weighing and dividing by density (1.76 g/cm3)
Write the data of the procedures and growth rate in the logbook.

5. What are Crystals?
A solid formed by the solidification of a chemical and having a highly regular atomic structure (Sodium Chloride is an example of crystals e.g. Table Salt.)

6. Atomic Structure

7. Chlorine Structure

8. Sodium Structure

9. Sodium and Chlorine Ions
Sodium, Na
Sodium is also in Group 1. It has one electron in its outer shell. When this electron is lost, a sodium ion Na+ is formed.
Chlorine, Cl
Chlorine is in Group 7. It has seven electrons in its outer shell. It gains an electron from another atom in reactions, forming a chloride ion, Cl-

10. Sodium Chloride

11. Sodium Chloride

12. What is this?

13. Diamond Structure

14. GRAPHITE

15. BUCKY BALLS

16. ALUM CRYSTAL

17. Crystal Concepts Basic concepts
Solvent- That which does the dissolving. (water)
Solute- That which gets dissolved (sugar)
Solution- Mixture of Solvent and Solute.
Solubility-amount of a solute that can be dissolved in a solvent.
The amount of sugar that can be dissolved in water.

18. GRAPH
The graph demonstrates how various solutes have variable solubility according to the temperature of the solvent.

19. Flow Diagram for Growing Crystals
SELECT MATERIALS
Water soluble ionic salts
WEIGH SALTS
Use 10% over RT saturation data
DISSOLVE
Heat purified water to speed up dissolution-but not to boiling. Stir with a clean utensil i.e. glass rod.
COOL TO RT
If solution was saturated a few crystals will be on the bottom.
FILTER
This step will remove undissolved solids that will cloud crystals.
GROW SEEDS
There are several methods of growing clear seeds. The best is utilizing a Petri dish. Protect from contamination by covering with filter paper.
GROW A BIG ONE
Select a large, clear, well formed single seed.
Tie string around the seed.
Suspend it in a large volume of liquor and
Replenish so as to keep the crystal suspended in the middle.
PREPARE DISPLAY
Board and log book

20. ALUM CRYSTAL