With a new baby in the house one summer, our usual adventures were on hold, and I had a bunch of bored kids on my hands. Easy science experiments like this magic crystal tree saved my sanity.
It uses a few household items, sets up in minutes and you can see crystals start to form in less than an hour. It’s perfect for kids just getting curious about science.
How to Grow a Magic Crystal Tree
Crawling Colors Science Experiment
Get the printablePlain, non-corrugated cardboard (like a cereal box with no gloss)
Markers or food coloring
1 tablespoon water
1 tablespoon salt
1 tablespoon laundry bluing (Mrs. Stewart’s)
1/2 tablespoon household ammonia
Shallow dish or tray
Cut two trees
Cut two identical tree shapes from the cardboard.
Slot them together
Cut a slit from the bottom up the middle of one tree, and from the top down the middle of the other. Slide them together so the tree stands.
Add color
Color the tips of the branches with markers. Have kids guess which color will show best.
Mix the solution
An adult mixes the water, salt, bluing and ammonia in a small bowl.
Pour and wait
Stand the tree in the dish and pour the solution into the bottom. You’ll see the cardboard soak it up right away.
Watch it grow
Crystals usually start within 15 minutes to an hour and keep growing for several hours.
Safety note
A grown-up should handle the ammonia and bluing. Mix in a well-ventilated spot, never mix ammonia with bleach, and keep the solution and crystals away from mouths and eyes. Look, don’t touch, and wash hands after.
How Does a Crystal Tree Work?
The cardboard pulls the solution up through tiny spaces in its fibers. That’s capillary action, the same way plants pull water up from their roots.
As the solution reaches the branches, the water and ammonia evaporate. The ammonia evaporates fast, which speeds things up. The salt and bluing are left behind and form the fluffy crystals.
It grows faster in dry air and slower on humid days. Kids also get to see evaporation, crystallization and saturation in action.
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Love science you can watch happen? Try our carbon sugar snake experiment.
The crawling colors experiment includes
- Step-by-step directions
- Prediction and observation sheets
- Simple science explanation
- Instant PDF download, nothing is shipped
Perfect for
- Science centers
- Homeschool
- Summer science
- Ages 4 and up
Crystal Tree FAQ
Stand a cardboard tree in a mix of water, salt, laundry bluing and ammonia. The cardboard soaks it up and crystals grow as it evaporates.
Usually 15 minutes to an hour to start, with more growth over several hours.
It’s in the laundry aisle at many grocery stores, or online.
With an adult handling the chemicals, yes. Don’t touch or eat the crystals, and wash hands after.
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From families like yours
Did you try it? Tell us how it went!
We love seeing these activities out in the wild: the lumpy letters, the snack breaks, the proud “I made a B!” moments. Leave a star rating, tell other parents what worked (and what totally didn’t), and add a photo of your setup if you’d like.
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Hello and thank you for this idea !
I intend to use it with my pupils. My question is: can you manipulate the tree afterwards ? As in removing it and taking it home without ruining the crystals. Doesn’t it smell too bad ?
I intended to use borax for a similar project, but I like this one better 🙂
Thank you for you reply !
Hi Alexandra-
It will be difficult to move around, the crystals are pretty fragile. And no it doesn’t stink 😉
How long do the crystals last once grown? would love to show this off at our art fair!
This varies a lot depending on environment. I would say anywhere from 2-8 weeks before they dry out and start falling apart. You can continue to “refresh” them by adding in more of the solution. To get them to last keep it in a dry spot away from air vents or fans where they aren’t being touched or bumped into.
Love this! Hoping to do for summer camp. I’m doing the experiment now and wondering how your liquid is clear? Mine turned bright blue with the gluing solution.