Kids, do real snowflakes melt a little too quickly for your full enjoyment? How about growing your own out of borax, coloring it blue if you like, and enjoying the sparkle all year long! Here is what you need: string, a wide-mouth pint-sized jar, white pipe cleaners, borax (see tips), a pencil, boiling water, optional blue food coloring, and scissors.
Please note: All chemicals and experiments can entail an element of risk, and no experiments should be performed without proper adult supervision.
Here is what you do. 1. Cut a pipe cleaner into three equal parts. 2. Twist the sections together at their centers to form a six-sided snowflake shape. This will be your scaffold or template. If an end isn't even, just trim to get the desired shape. The snowflake scaffold should fit inside the jar. 3. Tie the string to the end of one of the snowflake arms. Tie the other end of the string to the pencil. You want the length to be such that the pencil hangs the snowflake scaffold freely into the jar (not touching the bottom of the jar). 4. Take the snowflake scaffold out of the jar and ask your adult partner to fill it with boiling water. 5. Add borax powder, one tablespoon at a time, to the boiling water. Stir to dissolve after each addition. Use 3 tablespoons of borax per cup of water (1 pint = 2 cups). It is okay if some undissolved borax settles to the bottom of the jar. 6. If desired, you may tint the mixture with food color. 7. Hang the pipe cleaner snowflake into the jar so that the pencil rests on top of the jar and the snowflake is completely covered with liquid. 8. Let the jar sit in an undisturbed location overnight. 9. The next day, look at your pretty crystals! Remove the snowflake, dispose of the liquid down the drain, and re-hang the snowflake until it is dry. Then you can hang your snowflake as a decoration or in a window to catch the sunlight.
What is the chemistry here? This can be considered as an example of geochemistry. Borax is a complex borate mineral of composition Na2B4O7 -10H2O (hydrated sodium borate). It is formed in deserts from the evaporation of water in temporary lakes called playas. The playas form only during rainy seasons due to runoff from nearby mountains. The runoff is rich in the element boron and is highly concentrated by evaporation in the arid climate. Eventually the concentration is so great that crystals of borax and other boron minerals form.
Tips:
1. Borax is available at grocery stores in the laundry soap section, (e.g. 20 Mule Team Borax Laundry Booster). Do not use Boraxo soap.
2. Because boiling water is used and because borax isn't intended for eating, adult supervision is recommended.
3. If you can't find borax you can use sugar or salt. In these cases the crystals will take longer to grow, so be patient. Add sugar or salt to the boiling water until it stops dissolving. Ideally you want no crystals at the bottom of the jar.
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Kathleen Carrado Gregar, PhD, Argonne National Labs
[email protected]
February 2006
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Reference:
Dr. Anne Marie Helmenstine at:
http://chemistry.about.com/cs/howtos/ht/boraxsnowflake.htm?nl=1
