STEM Tuesdays: Borax Crystals

Have you ever stepped outside on a frosty morning and seen all the ice crystals around you? You might think it’s too warm for those crystals now, but today we’re going to make our own – and learn about chemical solutions in the process!

Note: Grownups will need to help with this activity.

Materials & Instructions

Borax
Water
Pipe cleaners or fake flowers – anything you want to crystallize
String
A heat-safe bowl
A long utensil like a butter knife or serving spoon
A measuring cup and tablespoon
A saucepan
A plate

STEP 1. If you’re crystallizing a pipe cleaner, form it into the shape or design you want.
STEP 2. Boil 2-3 cups of water on the stove.
STEP 3. Add Borax to your water and stir. Add 3-4 tablespoons of Borax for every cup of water used. We’re making a supersaturated Borax solution, so add in Borax until it stops dissolving in the water and you see some remaining in the bottom of your saucepan.
STEP 4. Transfer your Borax and water solution to a heat-safe bowl.
STEP 5. Tie your pipe cleaner creation, fake flower, or another object to your butter knife or another long utensil. Lower it into your warm solution until the utensil is resting securely across the top of the bowl and the item is suspended in the water. Try to get your creation close to the bottom of the bowl, but not quite touching it. 
STEP 6. Place a plate on top of the bowl so that it is loosely covered.
STEP 7. Wait. In the next 12-24 hours, you should see crystals form on the sides of the bowl and on your pipe cleaner creation or flower!
STEP 8. Once you are satisfied with your crystals, pull your object out of the solution and allow it to dry on a towel. 

What Happened?

In order to form crystals, we needed to create a solution by mixing together the Borax and the water. We were able to do this because Borax is soluble in water. That means that it dissolves in water like it did when you stirred it into your pot of water. However, it’s more soluble when the water is hot! As the water cooled, it wasn’t able to hold as much Borax as it could when it was hot. That Borax separated from the solution and formed crystals around your pipe cleaner creation and the sides of the bowl. 

Vocab Words

Saturate: When one substance (for example, water) absorbs or dissolves another substance (like Borax) until it cannot absorb any more. When we added more Borax than the water could absorb, it become supersaturated.
Solution: A mixture of two or more substances where one substance absorbs the other substances. In our case, we made a solution out of water and Borax. 
Solvent: A solvent is a substance in a solution that is able to absorb the other substance in the solution. In our solution, the water was the solvent.
Solute: A solute is a substance in a solution that is absorbed by other substance in the solution. In our solution, the Borax was the solute and it was dissolved into the water. 
Soluble: When something is soluble, it is able to be dissolved in another substance.