Growing Borax crystal is a really fun and easy experiment for kids. We were looking for some Valentine crafts to do and decide to make crystals again because it's been a few years since we've made them.
What You Need
- wide mouth jar (pint or quart)
- white pipe cleaners
- borax (sold in the Laundry soap isle)
- pencil or chopstick
- boiling water
- food coloring (opt.)
The first thing you need to do is to boil the water. You can make shapes out of the pipe cleaners while you are waiting. We made hearts, and then connected them together with string. Your shape needs to be small enough to fit inside the jar without touching the sides or bottom. basic shapes lie stars, spirals and snowflakes work well.
We usually use about two cups of water per pint jar. Our heart design was so long we had to use a quart jar, so we used 4 cups of boiling water for it.
i added the boiling water to the jar and let my daughter add the borax. You add 3 Tbsp per cup of water. We used 4 cups of water, so we added 12 Tbsp of borax powder. Stir after each spoonful of borax so it is mixed well. It's okay if some of the borax doesn't dissolve.
Then we added a few drops of red food coloring. You can add whatever color you like.
We tied our pipe cleaners hearts to a chop stick, so that is was suspended in the liquid, but not touching the bottom or sides. You could use a pencil or stick what ever you have on hand.
Then we waited.
The first time we made these the crystals began appearing almost immediately. Within a few hours the pipe cleaners were almost covered. This time we waited, but nothing happened. i was afraid we'd messed up the measurement, but i put it aside and left it to sit until morning.
When we checked it the next morning we were excited to see that it was covered in beautiful shimmery crystals!
We hung them in the window as a lovely suncatcher.
So how do the Borax crystals grow?
Hot water holds more borax crystals than cold water. That's because heated water molecules move farther apart, making room for more of the borax crystals to dissolve. When no more of the solution can be dissolved, you have reached saturation. As this solution cools, the water molecules move closer together again. Now there's less room for the solution to hold onto as much of the dissolved borax. Crystals begin to form and build on one another as the water lets go of the excess and evaporates.
*taken from britton.disted.camosun.bc.ca/snow/boraxsnowflake.html