See if you can grow beautiful, colorful crystals.
Time: 15 minute setup, 1-3 hours observing.
- Boiling Water
- Pipe Cleaners
- Glass bowl or mason jars
- Popsicle sticks, chopsticks, or pencils
- Food coloring
Please note that this project uses Borax, a common household cleaner/chemical and can be harmful if ingested particularly by the little ones. Use constant supervision and do not allow children to touch, eat or inhale Borax.
- Wrap the pipe cleaner once around the Popsicle stick and twist pipe cleaner into any desired shape (flower or star or spiral, etc.)
- Boil water on the stove and pour it into a mason jar (something that can withstand boiling water)
- Add a few drops of food coloring
- Add borax and stir into Mason jar until borax doesn’t dissolve any more (the saturation point).
- Suspend the pipe cleaner into the water/borax mixture by placing the Popsicle stick over the top of the jar
- Important: do not let the pipe cleaner rest near (or touch) the edge of the jar.
- Leave for 3 hours or more.
- What did you observe?
- Can you explain what is happening?
Borax is a substance that is in the form of crystal just like sugar and salt. So, how do the borax crystals grow on the pipe cleaner? The key fact is that hot water holds more borax crystals than cold water. When heated, water molecules move farther apart from each other which makes room for more borax to dissolve (same as hot tea dissolving sugar easier than cold tea). When no more of the solution can be dissolved, you have reached the saturation point. What happens when the solution cools? The molecules move closer together again. This means there is less room in the solution to hold the the same amount of dissolved borax. The result is that crystals begin to form and build on one another as the water lets go of the excess borax and evaporates.
- Try using different food colors and different amounts of food color
- Try using different pipe cleaner shapes
- Try using more or less borax in the mixture