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For those students requesting recipes for growing inorganic crystals, here ya go.
Be sure to have parental supervision and follow the safety precautions
appropriate for the reagents used in the experiment.
Growing a crystal gardenYou will need:
1. A plastic container, like
a large margarine tub
2. Pieces of charcoal, pieces of broken clay
flowerpots, and bits of sponge
3. Salt
4. Liquid laundry bluing*
5.
Household ammonia (Ammonia is an irritant. That means it will stink your nose
off. Keep it away from your face.)
5. A plastic cup
6. A tablespoon
7.
Water
Day One:
Put the charcoal and the fragments of pot and
sponge into the butter tub. Soak these parts in water for 15 minutes, then
drain. Sprinkle over the fragments:
2 tablespoon of water
2 tablespoons of
salt
2 tablespoons of bluing
This tub full will look pretty terrible
at the beginning.
Day Two:
Sprinkle on two more tablespoons of
salt. It will still look terrible today.
Day Three:
In the
plastic cup, mix together 2 tablespoons of salt, 2 tablespoons of water, 2
tablespoons of bluing, and 2 tablespoons of ammonia. Stir well and carefully
pour the solution into the bottom of the container - not on the crystals. It
still will look and smell like a horrible blue glop, but then it begins to
change....
Now what happens???
When your crystals stop growing,
mix up another batch of solution like you did for day number three, and spoon it
onto the materials. New crystals will form. You may also try adding some drops
of food coloring or watercolors to your garden.
*liquid laundry bluing
may be hard to find at your grocery store. You can write Mrs. Stewart's Liquid
Bluing at Luther Ford & Co, P.O. Box 201405, Bloomington, MN 55420. They
also have directions for a science project showing crystal growth.
Potassium aluminum sulfate dodecahydrateColorless. Cubic
system.
KAl(SO4)2·12H2O
Make the
following supersaturated solution:
1 a. 4 ounces of alum in
567 milliliters (19 ounces) of water
or
b. 20 grams per 100
milliliters of water
Add to the saturated solution:
2 a. 22
grams alum
or
b. 4 grams alum per original 100 milliliters of
water
If the crystals grow too quickly they will have many veils and
appear milky. To prevent this, reduce the amount of alum added in step
2.
Reference:
Crystals and crystal growing. Alan Holden and
Phylis Morrison, The MIT Press, 1982, ISBN 0-262-58050-0
BoraxNa2B4O7·7H2O
Add
one teaspoon of borax to 4 ounces of very hot water.
Stir until borax is
completely dissolved. When this solutions cools to room temperature little borax
crystals will grow.
Reference:
Crystals - A Handbook For School
Teachers by Elizabeth A. Wood 1972. Written for the Commission on
Crystallographic Teaching of the International Union of
Crystallography.
To obtain a copy of this book contact the Polycrystal
Book Service (Telephone & Fax: (513) 223-9070).
AlumNH4Al(SO4)2·12H2O
Add
4 teaspoons of alum powder to four ounces of hot water.
Stir until alum is
completely dissolved. Place a paper towel over the top of the jar containing the
solution and secure with a rubber band. This will prevent dust from entering the
solution but allow for evaporation.
After a period of time, given adequate
evaporation, alum crystals will appear.
Reference:
Crystals - A
Handbook For School Teachers by Elizabeth A. Wood 1972. Written for the
Commission on Crystallographic Teaching of the International Union of
Crystallography.
To obtain a copy of this book contact the Polycrystal
Book Service (Telephone & Fax: (513) 223-9070).
Epsom SaltMgSO4·7H2O
Add 6 teaspoons of
epsom salt to 2 ounces of hot water.
Stir until epsom salt is completely
dissolved. If all the salt does not dissolve, add a very small amount of water
and stir until all the epsom salt is dissolved.
Place a paper towel over the
top of the jar containing the solution and secure with a rubber band. This will
prevent dust from entering the solution but allow for evaporation. After a
period of time, given adequate evaporation, epsom salt crystals will
appear.
Reference:
Crystals - A Handbook For School Teachers by
Elizabeth A. Wood 1972. Written for the Commission on Crystallographic Teaching
of the International Union of Crystallography.
To obtain a copy of this
book contact the Polycrystal Book Service (Telephone & Fax: (513)
223-9070).
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