WARNING: Make sure to do the following project with an adult for extra precaution.

To Make Growing Crystals, you will need:

• A two cup canning jar or high heat stable measuring cup
• 1 ¾ cups of very hot water (aim for almost boiling)
• ⅓ cup of borax
• Pipe cleaner
• String
• A pencil

Instructions: 

1. Cut the pipe cleaner in half. Use one half and bend down the top in a loop that makes it look like a heart shape (or any shape you’d like). Twist the ends together at the point where they meet. 
2. Tie a string around the shape and then test it in the jar, before adding the liquid, just to make sure it’s the right length. It should hang half way down without touching the bottom or sides. 
3. Have an adult turn on your vent/exhaust fan on your stove to high and then slowly add the borax and stir. Stir it until the borax dissolves. Make sure the water does not become cloudy. Don’t worry if a little bit of borax remains. Be very careful not to add the borax to the boiling water or add it too quickly because it will boil over and make a big mess to clean up. 
4. Carefully pour the hot borax solution into your canning jar. 
5. Carefully lower the pipe cleaner heart into the water using the string attached. Then tie it to a pencil and set the pencil across the top of the jar. 
6. Set the jar in a warm place, but make sure that it will not be touched or bumped. 
7. Keep the pipe cleaner in the jar for somewhere between 6 to 20 hours. 
8. Then remove the pipe cleaner from the jar and allow them to dry for a day or two before truly handling or touching them. 

Cites:

https://childhood101.com/growing-crystals-science/