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


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.


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.


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.


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.


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.


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.



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.


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:


(White Coral, fine art photograph by Mary Deal, from

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.



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!

Super Cool Melting Ice Experiment


Lately, we have been up to our ears in ocean animal books and projects and notebook pages.  Apparently, it is a science subject that is going to stick around for a while.  But that doesn’t mean that we can’t get sidetracked every now and then.  Honestly, it’s one of the beauties of homeschooling.  Your child suddenly shows interest in something, you go with it, and the learning happens!  Not a bad formula in my book.

A while back, the kids and I participated in a “Brain Break” at one of our local churches.  It is hard to explain a “Brain Break” in just a few sentences, but basically the church uses it as an outreach to the schools in the area.  When there is no school because of a holiday or teacher in-service day, the church provides a full day of care for the students whose parents can’t afford to take off work for that day.  They feed the kids breakfast and lunch, do crafts, games, activities, science experiments, and more.  It is an amazing opportunity to serve others and to share God’s love with the kids.  I got to serve in a room where we taught the kids how to make their own snow globes before doing a fun melting ice experiment with them.  The experiment was a simple concept, but it held a definite wow factor for the kids.  My boys had a chance to try the experiment at “Brain Break” too, and they talked excitedly about it all the way home.  I decided we would replicate it at home.  I thought of a few modifications that would make it even more fun, and that night I secretly filled up four balloons with water and put them in the freezer.  The next day we popped those sparkling balls of ice out of their rubber casings and using salt and some food coloring, we conducted our science experiment and did a little art, too!

Want to get in on the fun?  You will need: a balloon, water, a large bowl, salt, and food coloring or liquid watercolors.  That’s it!

Fill your balloon with water, tie it off and put it in the freezer.  (Tip: put your water-filled balloon in a bowl in the freezer so that it does not get lopsided or ridged from your freezer shelves.) Let it freeze in there overnight in preparation for the experiment.  SCIENCE TIME:  How does the water change from a liquid into a solid when it is put into freezing temperatures?  You might already know that water is made up of molecules moving freely around, filling the space it occupies. Those molecules have three atoms each – two hydrogen atoms and one oxygen atom.   When you put water into a place that is 32 degrees Fahrenheit or lower, the molecules stop moving so quickly.  The cold slows them down.  Eventually they slow down to an almost standstill.  The oxygen atoms establish an organized pattern like crystals (remember those?), but the hydrogen atoms are rebels and go wherever they please.  This is why water expands, or get bigger, as it freezes.  If you put a bottle of water in the freezer with the cap screwed on tightly, it could explode from the water expanding as it freezes.

The next morning, put your frozen water balloon in a large bowl. (I have several colorful plastic bowls from the dollar store that we use for various occasions, and they worked perfectly for this experiment.) Use a scissor blade or knife to slit open the balloon and remove the rubber from your ball of ice.

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Just doing this will produce some “This is so cool!” responses or whatever the kids are saying nowadays.  Before we went any further in our experiment, I challenged the kids to hypothesize why there were these beautiful, sea-anemone-like structures inside our balls of ice.  Gabi guessed that it was the flow of the water as I filled the balloons.  David thought that maybe the water started turning to ice at the bottom and then moved out to the sides as it froze.  SCIENCE TIME:  Those were great hypotheses, but here’s the real reason for those crystalline structures inside the ice.  It may have seemed that I filled my balloon completely with water, but as I tied it shut, there was some air trapped inside the balloon.  If you look carefully at the first photo (the red one), you can see that the structure is actually made of hundreds of tiny bubbles strung together.  Those bubbles are the air trying to escape while the water froze.

Now comes the fun part.  Ask your kids to list some ways to melt or get rid of ice.  The kids at “Brain Break” certainly had some interesting answers to that question!  Inevitably, especially if you live in an area where snow and ice abound, someone will mention salt because they have seen it sprinkled on sidewalks and spread on streets during freezing winter weather.  Salt is what is used in this particular experiment to melt ice. So scatter (don’t dump!) some salt over the top of the ball of ice. The next part is hard – waiting for a few minutes while the salt starts to do its thing.  It’s a good time to discuss – SCIENCE TIME:  How does salt melt ice?  Here’s a quick video to explain it:

Or, if you want the Cliffs notes version, salt lowers the melting point of water.  Its atoms of sodium and chlorine disrupt the hydrogen and oxygen atoms of the ice and cause it to slowly break apart.

You may not be able to see the melting of the ice initially.  That is where your food coloring comes in.  We used food coloring because that’s what I had on hand, but if you can get liquid watercolors, I would recommend that.  Unless you like having rainbow-stained hands, then, by all means, copy us and use the food colors.  Choose a color and carefully squeeze a few drops over the top of your ball of ice.

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The salt actually sinks into the ice as it pushes aside the water molecules.  When the color is added, it drips down into these little pockets left by the salt.  This is clearly the art part!  Wait a little while and then add a few drops of a different color.  Try adding a little more salt.  You will notice that after each time you add salt, the surface of your ball of ice will become more dimpled like a golf ball.  It would take salt alone a very long time to melt this ball of ice.  It works more on the surface, which is why it is used on icy roads and walkways.

Other factors are at work in melting the ice.  Consider the temperature of the room you are in.  Is the sun shining through the window and perhaps directly on the ice?  Have you touched the ice at all with the warmth of your hand?  Now leave your ice alone for a while.  We went out to the library and the park before returning to see how our balls of ice were faring.

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You can see that our ice now resembled alien brains, as Mikey pointed out.  The tiny pock marks left by the salt had widened into larger pits like the finger holds on a bowling ball.  The water trickled down the sides in a snaky fashion as it twisted and turned around all the salt holes.  We added more color, which pooled up in the salt holes and streamed down the squiggly paths left by the melting ice.  We again left it alone for a while and came back to see new designs and patterns etched into the ice.  Each time we checked the ice, we were given a new art piece to admire and enjoy.  The kids left out their ice all night, and in the morning they came out to see their bowls filled with dark, cold salt water.

It was such an enjoyable and educational experience that we want to do it again.  What if we use something else beside a balloon to contain the water?  What will happen if there are substances in the water before it freezes?  What will the melting process look like if we use a hair dryer instead of salt?  There are a great many more possibilities, and my little scientists are eager to explore this new world of solids and liquids with more experiments.