Please pass the borax

Note: The children asked me to delay this post until after Christmas, so as to keep the gifts a surprise. One student later told me she checked December 26th to see if I had posted anything yet. Well. I certainly intended to . . .

As December approaches, Mrs. D. and I are on the look-out for creative homemade holiday gift ideas. This year, Kat Havens at the Houston Museum of Natural Science supplied the perfect solution (pun intended). Homemade crystal ornaments—science activity and holiday gift in one! Three cheers for Kat! We were already deep into geology, and then, just to make our crystal study even more relevant and exciting, it snowed! You see potential snowman, I see fabulous crystal lesson—potāto, potŏto.

"You have a few steps to make the ornaments we're making now.
Let's go over the safety rules. There will be hot water. You may step back when that step comes. You have to buy borax and save glass jars and have pipe cleaners and yarn. I think you can find borax inside Walmart in the washing materials section.
1) You make the shape of the ornament with pipe cleaners. Make something that fits in the jar without touching the jar with the pipe cleaners.
2) Second you need to make HOT water and pour it inside the jar and put about 6 or 7 scoops of borax. Stir until the borax dissolves.

"When you mix a solid and a liquid, that's called a solution! Solutions are fun!" --WL, 3rd grade
3) Tie the pipe cleaner to your pencil or pen and put the pipe cleaner in the glass jar. Make sure your ornament does not touch the bottom.
4) Let it stay in the jar for like 2 or 3 hours. You will need something on your hands while carrying the glass jar.
5) Then take it out and there will be crystals everywhere on the pipe cleaner. Then we will put a ribbon on it and after all that hard work you should have a nice ornament. Hang it on the Christmas tree or give it as a present. Happy holiday!!!"--CJ, MH, WL, KE, 3rd grade

The crystals we produced were hugely varied, and we got curious about why. Why did some ornaments sport large crystals and others develop tiny powdery crystals? We checked our ornaments and the same type of pipe cleaner had produced both varieties of crystals.

The same shape had produced both large and small crystals.

What could it be? We turned to what we know about geology. Volcanoes form a variety of crystal sizes in igneous rocks, depending on cooling time. Could THAT be what is affecting crystal size?


To check, we developed an experiment. How could we test whether cooling time affected crystal size? What could we do to speed up cooling time? Put it in a cool place---maybe the refrigerator, suggested a student. What could we do to slow it down? Put it in a warm place . . . or put something around it, maybe a towel. Another child pointed out that some of our jars already had crystals attached to the wall (leftover from a previous round of ornament-making) when we mixed the solution. Maybe that caused the difference in crystal size? We were careful to clean both jars before beginning our experiment. We used the same size jar, mixed a borax solution in a single container and then shared it equally between the two jars, used the same type of pipe cleaner, and formed the same shape with both.



With both jars equally full of borax solution and with their pencil/pipe cleaner/string combos installed,

we wrapped one with hot pads (a crystal cozy!)

and placed another in the refrigerator.

Hmm--not a lot different. Maybe something else is going on. Could it be as one first grader suggested, that some of our jars already had crystals attached to the wall? Could it be that some ambitious youth put more borax in the solution than others? Back to "the lab" for more experimenting! I smell a Science Fair project!



More of Kat’s creative Christmas crafts:
Christmas chromatography
Marvelous marbled ornaments
pH paper from a poinsettia