With the touch of her bare hands, “Frozen’s” Elsa coats the world with ice. It takes a little longer, but with your imagination, you can grow alum or Borax crystals on almost anything and make ordinary objects look extraordinary! (Directions for growing Borax crystals on pipe cleaners is near the bottom of this post. Borax crystals grow much faster than alum crystals and you can make snowflake ornaments overnight!)
We coated pipe-cleaner snowflakes, styrofoam snow people and even an evergreen branch with gorgeous ice-like alum crystals.
Here’s how to grow your own alum crystals:
Ingredients: alum (spice section of grocery store. 3 small containers for half recipe, 5 containers for 4 cup recipe. Alum is relatively expensive, so you might want to cut the recipe in half and crystallize smaller items! It’s cheaper to buy it in bulk at your local COOP.) glue, water, paintbrush,small items you’d like to coat with crystals.
1. Using a paintbrush, brush glue on the surface you want to “freeze”. One option is to twist 3 pieces of pipe cleaner together to make a snowflake. If you have beads, add them to your snowflake before crystallizing!
2. Before the glue dries, sprinkle the object with alum. These are your seeds for crystallization. Allow object to dry.
3.With adult supervision, dissolve about 1 1/4 cup alum in 4 cups in hot water (we use the microwave), reserving some alum to sprinkle on other objects you may want to make later. (One 1.9 oz. container of alum is around 1/4 cup, so you’ll need 5 of them.) Liquid will be cloudy and some crystals will sink to the bottom. This is your supersaturated alum solution.
4. Allow liquid to cool.
5. Suspend objects in alum solution until crystals are the size you’d like them to be. This may take an hour for small crystals or overnight for large one. Remove the crystals from the jar and dry your crystallized object. We grew big crystals on our snowflakes and then scraped them off the beads, but left them on the pipe cleaners.
6. To crystallize more objects, reheat alum solution, stir up crystals to dissolve as many as possible, and cool before adding the next thing to be “frozen.”
To make Borax crystals, dissolve 10 Tbs. Borax in 3 cups of hot water and immerse pipe cleaners cut and twisted into snowflake shapes in the liquid. You don’t even need seed crystals to do this, since the Borax crystals will form on the pipe cleaner fibers on their own!
The Science Behind the Fun: Some crystals, like alum, will form from supersaturated solutions, like the one you used in this experiment. A supersaturated solution is one that is forced to hold more atoms in water (or another solute) than it normally would. You can make these solutions using heat or pressure. Crystals can form when a supersaturated solutions encounters a “seed” atom or molecule, or another impurity in the solution (like a pipe cleaner fiber) causing the other atoms to come out of the solution and attach to the seed. The more molecules attach, the larger the crystal will grow. Here’s how to make rock candy with sugar crystals.
What else can you think of to crystallize?