Cool Science for Kids: Growing Crystals

This simple at-home science experiment lets kids create a fascinating chemical reaction--and make a sparkly memento, too.

"Sarah" out of pipe cleaners By Michael Piazza

BORAX, an old-school cleaning powder, is also a cool tool for teaching about minerals, the building blocks of rocks and earth. When lava hardens or water evaporates from a lake bed, the basic structures of minerals, called crystals, are often formed. Our experiment, in which pipe cleaners are submerged in a solution of borax and hot water, allows kids to see this process up close. As the mixture cools, glimmering crystals grow, and so do your child's scientific knowledge and curiosity. Safety note: Parents will need to supervise kids for this activity. Borax is generally considered safe for home use, but it should not be inhaled or ingested.

    Form the Base

    Bend pipe cleaners into cursive letters, trimming them and twisting on additional lengths as needed to form a name. For the starburst shape shown below, cut 4-inch lengths of pipe cleaner, cinch them in the middle with another pipe cleaner, then spread out the arms.

      Grow the Crystals

      Pipe cleaner crystal By Michael Piazza

      1. Using large paper clips bent to form hooks, hang the pipe cleaner shape on a chopstick or skewer. Suspend it from the rim of an empty plastic or glass container, making sure that it will hang without touching the bottom or sides. Remove it and set it aside.

      2. Wearing rubber gloves, fill the container with a solution made from 3 tablespoons of borax (available at many grocery and home stores, shelved with household cleaners) per cup of very hot water. Stir gently to dissolve the borax.

      3. Rest the chopstick across the top of the container so that the pipe cleaner shape is submerged. Leave it undisturbed for 6 to 8 hours or overnight. Remove the finished shape and pour the solution down the drain.