I recently did this science experiment with the kids in my Cub Scout group. One of the Scientist badge activities is to have them grow crystals. I read a tutorial on Martha Stewart’s website showing how to grow a geode using egg shells. Their scientist used alum powder, which is easy to find at most grocery stores…but can get expensive if you’re planning to make a lot of eggs. You can get similar results for a lot less when you use the common household detergent, Borax, to grow a crystal geode.
This makes a fun learning activity around Easter time because so many of us have an abundance of egg shells! Don’t toss them out – use them to teach your kids a little about how crystals are formed. Growing a crystal egg geode at home is pretty cool any time of year.
Here’s what you’ll need to grow crystal geodes. And how to do it, of course!
- Egg Shells
- White glue
- Small paintbrush
- Hot Water
- Food Coloring
- One jar per every egg shell
- PREP EGG SHELLS AHEAD OF TIME: You will need to prepare your egg shells by peeling off the inner membrane. Wash and dry the egg shells, then head to step 2.
- Use a small paintbrush to paint the egg shell inside and out with a layer of white glue. Allow to dry completely overnight.
- Prepare as much of the hot water/borax solution as needed for your jars. Use 3 Tablespoons of Borax for every 1 cup of boiling water. Stir until Borax is completely dissolved and pour into jars. I used about 1 cup per jar (use enough water to completely cover your egg shell in the following steps). Add a few drops of food coloring to each jar.
- Carefully place one egg shell per jar. Make sure the shell is submerged in the borax/water solution. Put the jars in a place where they will not be disturbed. Allow them to sit overnight. Crystals will begin forming as the solution cools.
- Remove egg shells from jars and allow to dry.
It took about an hour for me to be able to see the crystals beginning to form on the egg shells. The egg shells in my photos show crystal formation after 8 hours in the solution.
I found this Borax Crystals Science Experiment worksheet full of helpful information that explained the science behind the crystal formation. It’s from the Discovery Museum Science and Space Center at www.discovery.org
Have you ever grown borax crystals? Have you tried the alum crystal method? Let me know if you try to grow crystal geodes on egg shells! Feel free to leave photos on my Facebook page.