December 2016

Colorful Crystal Creations (12/7/16)

crystal-3  crystal-2  crystal-1

MATERIALS:

  • Heat-resistant jar or glass (wide-mouth mason jars work very well)
  • Pipe cleaners (sometimes called chenille stems)
  • Pen, pencil, or chopstick for an anchor
  • Paper clips or a piece of string
  • Microwave
  • Spoon
  • Water (sometimes called dihydrogen monoxide)
  • Water-soluble crystals (powdered Alum, Borax, Salt, etc)
  • Paper towels
  • Food dye

INSTRUCTIONS:

  1. First we need to create the form that our crystals will grow on.
  2. You can use a variety of craft supplies to make a base for your crystal creation. I recommend using chenille stems because they are super easy to mold into any shape, and their fuzzy fibers are wonderful for crystal-growing! But you can get crazy creative!!
  3. Be sure that your final shape is a bit skinnier than the opening of your jar or glass (if your crystal form grows too wide, it might get stuck inside of the jar!)
  4. To create a hanger to hold your crystal shape, simply bend outward the inside loop of a paperclip to create a flattened S-shaped hook. Thread one end of this paperclip hook through a loop in your chenille stem shape, and hang the other end over the center of your pencil anchor (or pen, or chopstick).
  5. Now we need to mix together a super-saturated solution that our crystals will grow from.
  6. Fill your heat-resistant jar ¾ full of water (H2O), leaving enough room to add the water-soluble crystals in the next steps.
  7. With some help from an adult assistant, Microwave your water jar on high for 2 – 2½ minutes. Carefully remove the container and allow it to cool in a safe location for about a minute. Be careful, because it will be hot!
  8. While the water is still quite warm, add your water-soluble crystals to the water one spoonful at a time, mixing thoroughly after each addition. Continue to add the crystals until they will no longer dissolve into the solution. You may notice a bit of crystals settle down to the bottom of the container; this means that we have fully saturated your crystal solution! But you need to add one MORE spoonful of crystals! *If you would like to add color to your crystals, add a few drops of food dye to your solution at this time.*
  9. Ask your adult assistant to Microwave the crystal solution on high for an additional 3 minutes, or until you see small bubbles rising through the water.
  10. Remove the jar from the microwave, and CAREFULLY stir the crystal solution one final time. It will be VERY hot! You should see that most (if not all) of the crystals have now fully dissolved into the water. Our solution is now supersaturated!
  11. Carefully balance your pencil anchor on the top of your crystal-growing container. Make sure that your chenille straw shape hangs in the very center of the crystal container, and also that it is fully submerged in the solution (if it is not, you may need to straighten out the paperclip hook, so that it will hang down further).
  12. Let your crystal mixture sit, undisturbed, for at least 20 minutes. Be sure to check on the container for any changes to the solution during this time. You should see crystals forming within 30 to 45 minutes, but the crystals will continue to grow for the next 6-8 hours—or you can leave it overnight for the biggest results.
  13. When you are happy with the amount of crystal growth on your creation, carefully lift the paperclip hook from the pencil hanger, and lay down your crystal shape onto a dry paper towel. Dab off any excess crystal solution. You can remove the paperclip hook from the crystal shape, or simply use the upper loop as an ornament-hook.
  14. Enjoy your shiny, sparkly creation!

HOW DOES IT WORK:

crystalline solid is a solid material that is made up of atoms or molecules that are arranged in a particular structure, or pattern. This structure is known as a crystal lattice. Although the microscopic crystal lattice of our crystals can only be viewed under very high magnification, the crystal will grow in geometric shapes that are characteristic of the substance itself.

There are lots of examples of crystals in the world, including mineral rocks and several gem stones, table salt, and even ice. But there are only a few basic shapes into which these crystals will grow. Here are a few of the basic crystal shapes:
3-d-shapes

**Use a magnifying glass to identify crystal shapes growing on your creation, or even the crystal shape of table salt!**

Many students will wait days or even weeks while performing the traditional experiment of growing crystals in a cooled solution of dissolved crystals. A solution is a mixture of two or more substances: a solute is the substance that is dissolved into the solvent. In our experiment, the water-soluble crystals are the solute, and water is our solvent.

But the secret to quickly growing crystals is to create a supersaturated solution, meaning there is more solute than would normally mix into the solution. By heating the water, we energize the water molecules. This makes the water molecules spread apart and make extra room between them for extra crystal solute to squeeze into.

As the solution cools, the water molecules begin to slow down and move closer together again. This forces the dissolved solute out from between the water molecules and they gather together into their characteristic crystal lattice structure, coating all surfaces within the container (and most importantly, coating our chenille straw form!) with shiny crystals!

THE MORE YOU KNOW:

snowflake forms from water molecules in the cold upper atmosphere. On particularly chilly occasions, the low temperature slows down the normally quick movement of the water molecules until the attractive force between them actually pulls them together into a solid. In other words, they freeze into ice!

High in the sky, ice molecules tend to grow around dust particles in a simple arrangement of ice crystals: six water molecules bond together into a six-sided (or hexagonal) shape. This simple ice crystal is the seed crystal on which the snowflake will begin to grow (scientists call these tiny crystals “diamond dust”). Because the six points of the hexagon reach out the furthest, other freezing water molecules are more likely to attach to these points. The needles grow outward, forming seemingly unique ice crystals, but usually with only six main branches.

For a really cool look at snowflakes, check out the work of Wilson Bentley (he devoted much of his life to photographing snowflakes!)

GOING ONE STEP FURTHER:

  1. If you want to crystallize a formation that is bigger than the opening of your heat-resistant container, why not try using a heat-resistant bowl or plate? You can twist together chenille stems into much wider, flat creations (like a snowflake, maybe?) and place it on a deep plate or flat-bottom bowl. Carefully pour in enough of the supersaturated crystal solution to fully cover your shape, and wait… Be aware, you might knock off a few of the crystals while lifting up your crystallized formation.
  2. Do you want to grow really large crystals? After growing a crystal shape, don’t throw away the small crystals that form on the sides and bottom of your container; instead, you can use the biggest and prettiest crystals as seed crystals to grow even larger ones! Carefully tie a piece of string around your seed crystal, and hang it from your pencil anchor instead of a chenille stem shape. Repeat the experiment using the same crystal several times to see how large you can grow your crystals!
  3. Or how about really sweet crystals? While many of the water-soluble crystals listed above are not edible, or at least not tasty. But there’s another water soluble crystal that we neglected to mention: Sugar. You can make your very own Rock Candy Creations right at home! Now that’s some tasty science!