Crystal Science: How to Make Your Own Magic Crystal Coral Reef

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A few months ago, the kids and I played around with making our own crystal snowflakes. (how to and amazing results here)  It really had nothing to do with anything we were studying but hey, it was winter and we weren’t getting any snow so we needed to make our own. Or something like that.

Anyway, we loved growing the alum crystals.  I spent some time on Pinterest looking for other ways to grow crystals.  Currently, I have pinned to my Science board to try these sparkly crystal geode eggs (good Easter project, anyone?) and these overnight crystal gardens.  While I was perusing the many ideas on the internet, and pondering many sciency things, I remembered the magic crystal trees that I had purchased as a kid and then grown at home.  Does anyone else remember these?  Apparently, there are still versions of those scientific little wonders for sale.  When I saw the familiar puffy crystal branches, it immediately made me think of coral.  What if we could grow our own magic crystal coral reef?  That would fit in perfectly with our ocean unit study.

If you search “how to make your own magic crystal tree,” you’ll find dozens of websites with clear instructions.  It seemed like it would be fairly easy to adapt it to a piece of coral instead of a pine tree.  And so we attempted to make our own crystal coral reefs with fantastic results.  Get these supplies if you want to try it for yourself:  one or two pieces of cardboard, table salt, ammonia, Mrs. Stewart’s bluing, scissors, pencil, water, food coloring, and a glass dish.

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First, you will need to draw and cut out your coral shapes from the cardboard.  (Note about the cardboard:  it cannot be coated, like cereal box cardboard, and should not be too thin, as it would fall over with the weight of the crystals.  I used the cardboard backs of some legal pads I had.  They worked perfectly.)  The kids looked up pictures of various types of coral online and chose two different ones to draw.  Draw it once on the cardboard, cut it out, and then trace it again on the cardboard to be cut out a second time.  You can see that we tried a short coral version and a tall one.  Don’t make it too tall!  Cut a slit from the bottom center of one of your cardboard pieces halfway up the design.  Cut another slit on the other piece of cardboard halfway down the design.

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Now you can put your pieces together to give your coral a 3D effect.  Simply slide the two slits together and spread the piece apart until they stand nicely, as in the photo above.

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Next, it is time to mix your solution.  (A word of warning: keep your work area well-ventilated as ammonia has a very potent odor!)  In your glass dish, mix the following:  3 TBS bluing (get it in the laundry section of your grocery store), 3 TBS water, 3 TBS salt, and 1 1/2 TBS ammonia.

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Then drip some food coloring over your cardboard coral structure and carefully place it into the solution in your glass dish.

Now comes the waiting part, but don’t worry, you won’t have to wait long.  The next day, Mikey came racing into my room shouting that I needed to come and see the coral now.

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Sure enough, tiny delicate salt crystals had gathered on all the points of our cardboard coral reefs.  It is near impossible to avoid with over-excited children, but please do your best to not touch or bump the crystals in any way.  They are extremely fragile.

Two days later, the tiny salt crystals spread out over the cardboard a little more.

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The kids were delighted to find blue, green and yellow tinged crystals sprouting up everywhere.  For some unknown reason, the crystals were unaffected by the red food dye.  In a few more days, the shorter coral structure was almost completely covered in crystals while the taller structure experienced crystal growth about three-quarters of the way up.

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At this point, the finely detailed, sharply pointed crystals of the first two days softened into a more pillowy design.  Doesn’t it look a lot like coral?  Check out the similarities:

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(White Coral, fine art photograph by Mary Deal, from fineartamerica.com)

The crystals do not last more than a few days before they start falling and shattering into little piles of powder.  However, seeing a simple piece of cardboard burst into hundreds of beautiful little crystals is pretty amazing.  And of course, being a good, responsible homeschooling mom, you are going to want to know the science behind it all, right?

We already talked about crystals and how they form in this post.  In this experiment, crystallization does take place, but only after some other scientific processes occur first.  The first process that has to happen is capillary action.  That’s really just a couple of fancy words to describe how liquid sometimes defies gravity and goes up instead of down.  In plants, water can travel up thin tubes called capillaries to give the entire plant the necessary hydration for survival and growth.  You can see this happen when you stick a stalk of celery into a glass of colored water.  If the tubes are skinny enough, the surface tension of the water enables it to basically “climb” up the walls of the tubes.  Liquids will also climb the fibers of a piece of paper or cardboard.  This video is a great demonstration of this:

In our coral crystal growing experiment, the solution in the glass dish climbed up the fibers of the cardboard.  That’s when the next scientific process took place – evaporation.  Evaporation is the process of liquid molecules escaping and becoming gas molecules instead.  We put ammonia in the solution because it evaporates much faster than water.  The ammonia and the water molecules escaped the cardboard and became gas molecules.  The bluing and the salt were left on the cardboard to begin the next process – crystallization.  Because the solution was so saturated with the bluing molecules and the salt molecules, these molecules are able to combine and form crystals, much like we discovered in the previous post about crystals.  The bluing is a colloid, which is one substance that has another substance evenly dispersed throughout it.  Some good examples of colloids are mayonnaise, our blood, and hair gel.  (You can watch this little video by Martha Stewart on how to make your own colloid with starch and water that does some pretty cool things!)

Oh, and since this is part of our ocean study, it might be a good idea to study up on coral – what is it, where do you find it, and why is it important to the earth?  There are lots of resources online for this, but I’ll leave you with two.  First, here is a link to a free homeschool unit study on coral reefs.

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And, as always, here is a short but educational video on coral reefs:

Have fun learning about these magnificent structures of the deep as you make your own magic crystal coral reefs!

Crystal Science – Make Your Own Snowflake

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Back when we were in a flurry of activity (ha, do you see what I did there?) preparing for Hosanna’s Do You Wanna Build a Snowman party, the older kids became obsessed with snow and snowflakes and basically anything white and cold and fun.  We rarely get any real snow around here; so we settled for cutting out paper snowflakes, spraying fake snow in our windows, and building snowmen with homemade magic snow (link here to awesome recipe).  One day, when everyone was going stir crazy and I was desperately trying to think of a fun but educational activity to do, I remembered a crystal growing project I had done with my General Science class at home school co-op.  I figured that we could take out the typical string and use something else to make it into a snowflake.  The results ended up being quite sparkly, perfect for our snow obsession as well as a little lesson on crystals.  Here’s how to make crystal snowflakes and learn a little about crystals at the same time.

If you google “growing crystals,” most sites will give you a formula using borax.  Borax is great and is pretty sturdy; but alas, I did not have borax when we commenced this experiment.  I decided to use alum instead.  Alum makes beautiful crystals that are much more fragile and will not last a long time; however, they grow very quickly and you will see results within hours.  When you purchase your alum, make sure it has potassium in it or crystals will not grow.  I got mine in the spice section of the grocery store.  (In case your kids ask you what alum is, its official name is potassium alum, and it is used for pickling and other household activities.  It is also found in your can of baking powder, unless you buy the fancy expensive kind in the natural foods section labeled “without alum.”)

For this experiment, you will need:  alum, a white pipe cleaner, a drinking glass or mason jar, a pencil, another pipe cleaner (any color), fishing line or thread, scissors, and water  (You also need a small pan and access to a stove.)

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First, prepare your materials.  Cut the white pipe cleaner into three pieces of equal length and then twist them together in an asterisk shape. *  Tie a piece of fishing line or thread to one of the points on your “snowflake”.

Now, make your solution.  Put enough water to fill your glass or jar into a small pan and heat it to boiling on the stove.  When the water is boiling, remove the pan from the burner and wait for the boiling to stop.  As soon as the boiling stops, start adding alum to the water and stirring with a heat-resistant spoon.  Keep adding alum until it will no longer dissolve.  (This is evident when the water is cloudy and will not clear up.)  Allow the solution to sit in the pan for a few minutes until it is again clear and any extra alum has settled to the bottom of the pan.

Next, set up the experiment.  Carefully pour the solution into your glass or jar until it is high enough for your snowflake to fit.  We used a juice glass and filled ours about three-fourths.  If you can, try not to pour the alum that has settled in the bottom of the pan into your glass.  This is called decanting, or separating a mixture into liquids and sediment.  As you can see in the photo, we were not terribly successful in our decanting.  Then take your pipe cleaner snowflake and dangle it in the solution.  It is very important that the points of the snowflake do not touch the sides or the bottom of the glass.  When you have it at the right place, tie it to the pencil and reinforce it by wrapping it with the other pipe cleaner as shown in the picture.  DSC_0017

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Be sure to put your set-up in a safe place out of the way.  We set ours back on the kitchen counter where they couldn’t be disturbed for several hours.  (Also, we have a certain three-year-old around here who loves to stir things up and add things as she “cooks” so….)  As you can see, each child had his own snowflake to grow.  We have a color system in our house that makes life so much easier.  Gabi’s color is green, David’s is blue, Mikey’s is orange, and Hosanna’s is purple.  That means Gabi drinks out of the green cup, uses a green plate, has a green bin for her shoes, etc.  It makes it a breeze for me to know who left their cup in the living room again, and most importantly, there is no arguing.

Anyway, I digress.  Call it a free tip.  So let your experiment sit for several hours, checking on it from time to time by looking through the glass, NOT by touching it.  After several hours have passed, or the next day as I like to call it, carefully use your pencil to lift the snowflake out of the solution and lay it gently on a clean surface.  Remember that the alum crystals are very fragile and have a tendency to get knocked off easily.

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This is when you get to do the observation of the snowflake.  Have the kids touch it and feel the various shapes that make up the crystals.  Look at the crystals with a magnifying glass.  See if they can find a repeating shape or pattern in the snowflake.  Gently tap one point of the snowflake with a pencil to knock off some crystals and examine those crystals more closely.  What do they look like?  Are they symmetrical?  Then you can teach the kids some facts about crystals.

Facts about Crystals: Going Beyond the Fact that They are Super Sparkly and Very Fun to Look At

1.  What is a crystal?  It is a mineral that is made up of molecules that form a repeating pattern.  These molecules band together to form a shape that is then repeated over and over again.  Take out a crystal of sugar and look at it under a magnifying glass.  Do you see that it is shaped almost like a football?  Now look at a crystal of salt.  You should see that it is shaped like a cube.  What shape did you find in your snowflake?

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In this picture, you can see points that look like pyramids.  Alum crystals actually have an octahedron shape (two pyramids stacked on top of each other).  There were actually dozens of nearly-perfect octahedrons on our snowflake the second time we did the experiment, and they were all visible without a magnifying glass.  When studying crystals, you will find hexagons, tetragons, and other shapes as well.

2.  Where do crystals come from?  Crystals form in two different ways.  The first is by evaporation of water from a mixture.  This is what we did in our experiment.  As the water evaporated, the alum powder formed into tiny crystals.  The second way is by cooling of a liquid as it starts to harden.  Expensive crystals like diamonds are formed when magma hardens slowly over time.  Maybe you have seen rubies, emeralds, and amethysts.  These are all crystals that have formed in nature by evaporation or cooling.  Of course, snowflake are ice crystals that form when water cools very quickly in the atmosphere.

3.  Why do crystals have sharp edges and angles?  Crystals have symmetry.  Symmetry is just a big fancy word that means “the same all around.”  There are a few different kinds of symmetry that you can find in crystals.  The first is called rotational symmetry.  Basically it means that when you spin the crystal around, it is the same from all sides.  Think of a ferris wheel.  Every time you spin it, it looks exactly the same.  The second kind of symmetry is reflection symmetry.  In this case, one half of the crystal is a mirror image of the other.  Think of a butterfly and how the wings look like a reflection of each other.  The third kind of symmetry is inversion symmetry.  Imagine that you can put a straight line through the center of the crystal and then spin the crystal around that line as if it were an axis.  This is what you see in our experiment.  It is very similar to a toy top.

Want to know more?  Learn what the terms cleavage, isometric, and monoclinic mean, and find out what crystals are used for in the videos below.

And if you want to watch a snowflake form its crystals in time lapse, check out this link!  It is very mesmerizing and illustrates all the principles of crystals we have learned.