About Borax Crystals

In recent years, borax has become quite popular with the preteen set. Why? Because it's a key ingredient in making homemade slime. It's easy to make slime with white glue, water and a small amount of borax. Add food coloring and glitter, and you've got yourself some fancy slime that will amuse you and your friends for hours. Apparently, kids are also selling slime at school right now too. It's entrepreneurship mixed with science and sounds like a pretty positive preteen activity.

You can make crystals out of borax, water and pipe cleaners. The process, called recrystallization, occurs when a substance, such as borax, is dissolved in hot water and then cooled slowly. Crystals appear because of solubility, or the largest amount of something that can be dissolved in something else. In this case, borax in water. Solubility typically increases with temperature, which is why the crystal experiment with borax requires dissolving the powder in hot water. Stick a pipe cleaner into the mixture while it's cooling. When it's cooled, more borax is in the mixture than can be contained by the colder water, so borax falls out of the mixture and clings to the pipe cleaner, forming crystals.

For this experiment/craft project, you'll need a container, water, borax, pipe cleaners and food coloring (optional).

1. Bend pipe cleaners into the shape you want your crystals to grow. If you want to make a geode, spiral several pipe cleaners into a hollow rock shape. Imagine it as the "bones" of a geode. If you want to make a snowflake, cut and bend two pipe cleaners into a snowflake shape.
2. Boil water, then allow it to cool a bit.
3. Mix in a small amount of borax. Keep adding borax until it stops dissolving in the water (this is when solubility is occurring).
4. Add food coloring to the mixture if you want your crystals to have color.
5. Pour your mixture into a container that's slightly larger than your pipe cleaner structure.
6. Set your pipe cleaner form into the mixture.
7. Cover the container with a dish towel and place in a warm spot, such as a sunny window. The slower the mixture cools, the better the crystals will form.
8. Wait a couple of hours, then check your structure and dislodge it from the container. At this point, there should be some crystals covering your pipe cleaners.
9. If you want more crystals or your object isn't covered yet, repeat the process. New crystals will grow on top of the current ones.
10. Repeat until you're happy with your geode or other crystal-covered shape.

This experiment is particularly fun because at the end you have something to play with. The ingredients for this project are almost the same as for slime, but cornstarch is added to the mix.

Ingredients: One tablespoon of white glue, half a teaspoon of borax, food coloring, three tablespoons of cornstarch and four tablespoons of warm water.

1. In one bowl, add the glue and a few drops of food coloring.
2. In a second bowl, mix together the borax, cornstarch and water, and stir well.
3. Pour the borax mix into the glue bowl.
4. Stir until you create a big glob.
5. Remove the glob and roll it between your palms to form a ball.
6. Keep rolling it between your palms until the stickiness is gone.
7. Bounce the ball!

The popularity of slime making has raised concerns about the safety of handling borax. While there's no definitive answer, several experts have weighed in to say the small amount of borax used for making slime or other science projects isn't really enough to be absorbed through the skin and cause harm. As long as your children don't ingest borax – especially in large quantities – they should be fine. But, of course, that's a judgment call a parent should make on their own.