Step-by-step tutorial
Warning
Borax can irritate skin, especially with prolonged contact or for kids with eczema or sensitive skin. Want a borax-free version? Salt and baking soda grow crystals too, but they need different amounts and a lot more patience, so follow a recipe built for them rather than swapping them into this one. Either way, wash hands after handling the crystal and keep away from eyes and mouths.
Step 1
Gather your materials.
Step 2
Shape and tie pipe cleaners into a rainbow.
Step 3
Fill a jar with 3 cups of hot water.
Step 4
Pour in ½ cup of borax.
Step 5
Stir until dissolved.
Step 6
Use string to tie the rainbow to a pencil.
Step 7
Hang the rainbow in the water-borax solution and let it sit overnight.
Step 8
Pull out the now crystallized rainbow and let it dry.
Step 9
Once fully dry, see how your crystal rainbow came out!
Learn more
When you mix borax into hot water, the heat causes the water molecules to spread out, allowing them to hold way more borax powder than cool water can. This creates a special solution called a "supersaturated solution." As the liquid cools overnight, the water molecules squeeze back together and can't hold all that extra borax anymore! The extra borax particles lock onto the fuzzy fibers of the pipe cleaners, stacking together in repeating patterns to form hard, shiny crystals.
