Our Project:  Grow Crystals

Our Props:
A yard of yarn
Two jars
One bowl
Two paper clips
Baking soda

Our Plan:

• Find a permanent spot to keep an experiment for several days.  Set up the bowl with the jars or glasses on each side.
• Take the yarn, fold in half and then fold it in half again.   Now twist the yarn and make sure you twist tight.
• Attach the paper clips to either end of the yarn.
• Place each end of the yarn in the jars.  Drape the yarn over the bowl so there’s a dip over the bowl.
• Stir baking soda into hot tap water.  How much?  Enough baking soda to saturate the water.  Add baking soda and stir until it doesn’t dissolve anymore.   When you can see baking soda in the water after you’ve stirred and it doesn’t dissolve, you'll know the water is concentrated.
• Add the baking soda solution to each jar.  Store the extra in a closed jar to add to the jars as needed.
• Moisten the yarn and then watch the experiment.  You should see crystals growing in a couple ofdays.  Be sure to keep the jars filled with the saturated water solution.
• Add solution to the jars as needed during the week.   Keep this experiment up for a week or until you think the yarn won't hold another crystal.

Have fun, Devokids!

VOCABULARY

• Catenary:  A curve hanging from two points from a chord or chain.  (The dip in the twisted yarn.)

Catenary Equation for Math Brainiacs:  y = k cosh(x/k)

• Sodium Bicarbonate:  NaHCO3    Baking Soda is a white, water-soluble powder.
• Saturated:  Containing the maximum amount of solution (solute) capable of being dissolved under any conditions.  (Dictionary.com)

Resource: http://chemistry.about.com/od/crystalrecipes/a/sodacrystals.htm