Egg Geodes Experiment

Today we’re experimenting with egg geodes. This experiment is set up to engage children in the steps of the scientific method, which could easily make this a fun and successful science fair project. Not only is the process of making these beautiful geodes engaging for kids, but the end-result has a huge wow-factor. Give yourself at least two-three days to achieve the greatest results.

Egg Geodes Inspiration

I was inspired by these egg geodes that I spotted on Martha Stewart and then followed this recipe by Melissa Howard who blogs at Those Northern Skies. If you enjoy this post, do click over and see what these two sites have to offer. The pictures alone are worth looking at.

egg geodes

Set up the Egg Geodes Experiment

Supplies

  • Eggs
  • Rock Salt
  • Sea Salt
  • Borax*
  • Other substance that could be tested for crystallization such as sugar, epsom salts, cream of tartar, baking soda, or alum*
  • Mini-muffin pan
  • Food Coloring
* Borax and alum are not food products, and using these ingredients with small children should be closely monitored, as ingestion can be fatal. Please use common sense and close supervision with such substances. My children were watched at all times and did not come in direct contact with borax in the process of this experiment.

clean membranes from eggsI tapped a knife around the top of the eggs to remove a bit of shell, and then emptied the eggs and cleaned them with water. Using a finger, it’s important to gently rub around the inside of the egg to remove the membrane because the membrane can discolor crystals as the form.

If you happen to have a mini-cupcake pan, it’s like they were made for this job.

add salt to water for geodesWe heated a pot of water (not quite boiling) and then poured 1/2 cup into a mug. We added 1/4 cup of kosher salt into the first mug and mixed it until it dissolved.

The kosher salt was stubborn and wouldn’t dissolve, so Nutmeg handed the mug to me for some rigorous mixing. Sill no luck.

We moved on to the next mug: 1/2 cup hot water + 1/4 cup sea salt. The sea salt dissolved quickly and then we added a bit more. The idea is to saturate the solution without putting in too much of the dry ingredient.

And then the final mug: 1/2 cup hot water + 1/4 cup borax. Dissolved.

geode chartWe added a coup;le drops of food coloring to each mug and then made a chart so we wouldn’t lose track.

Then we poured the liquid into our eggs. Each solution made just enough to pour into two eggs. Perfect!

And then you wait. 5  days for the liquid to mostly evaporate.

We couldn’t that long, but after 1 day salt crystals evaporated through the egg shell, and after 2 days our eggs looked like this…

egg geodes

egg geodes

Kosher Salt 

Through the process of diffusion, the salt actually passed through the permeable shell. Gorgeous, isn’t it?

egg geodes

Sea Salt

egg geodes borax

Borax

With opposite results of the salt-solutions, borax created the most sparkly, crystal-looking egg with crystals inside the egg and nothing on the outside.

And of course, things like this are irresistible to little hands. My toddler wanted to pick all the crystals off the shells, and I had to pull them away because not only will she break them into a gazillion pieces, but substances like borax are safe for looking, not for touching.

So, if this strikes your fancy, have fun testing some of the different soluble solids mentioned in the list above.

egg week

This is Day #4 of Egg Week, which I’m co-hosting with my talented arts education friend Melissa who runs the popular children’s art blog, The Chocolate Muffin Tree. Take a minute to hop over to The Chocolate Muffin Tree and see the egg surprise she has in store for us today.

And if you’re just catching up with us, here’s a look at what we’ve covered this week so far:

 

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Comments

    • Rachelle says

      Love that you’re doing it! Yay! Please report back and send me a photo! radoorley at gmail.com

  1. Sueecampbell says

    This looks like a great idea and I will definitely be trying this, thank you. I am concerned with your little girl touching the borax crystals though.
    Everyone should be aware that borax is toxic and can result in adverse symptoms. Some of the symptoms of Borax ingestion include headache, fever, nausea, vomiting, and red eyes. People should be very careful about their small children handling water soluble borax by making sure that they wash it off quickly .

    Symptoms may appear 2 to 4 hours after ingesting Borax.

    The best way is to never eat Borax and never use it in food.

    • Rachelle says

      Thanks for the shout out for caution, Sue! Because we use these substances with close supervision I sometimes forget that other people may not know about these things. In the photo above, my little one is handling the kosher salt crystals. I made a correction to the post that I hope clears this up for concerned readers. Cheers!

    • Rachelle says

      Thanks for the shout out for caution, Sue! Because we use these substances with close supervision I sometimes forget that other people may not know about these things. In the photo above, my little one is handling the kosher salt crystals. I made a correction to the post that I hope clears this up for concerned readers. Cheers!

  2. says

    How am I only now hearing about this fun with eggs?!? My kiddos love anything that involves eggs! I have used them for quite a few different “experiments”, who knew you could so much with them?! I will definitely be doing this one.. and now I’m off to read about all of the other ‘eggtivities’ you’ve done so I can do those too! Thanks :)

    • Rachelle says

      Who knew? And to think that we had to stop ourselves with just 10 egg projects! But guess what, I’ve been collecting egg ideas from my blogging friends, and will have even more for you next week :)

  3. Growingajeweledrose says

    So cool!  I am just loving all the ideas you and Melissa are sharing this week!

  4. Lesley Ann Rodriguez says

    Now, where to find Borax?  But not sure yet if we’ll do this!  My little one is a riot and I doubt I can control his excitement and NOT let him get his hands on the finished product!

    Les
    from LPN Programs

    • Rachelle says

      Hee hee. I found it in the laundry aisle at Target. It comes in a powder form, and looks kind of like a box of Tide or similar laundry soap. 

  5. says

    We tried this experiment with salt, borax, sugar and Washing Soda on our blog http://raisingourfamily.blogspot.ca/2012/04/egg-experiments.html the Washing soda had the best results for us.  Thank you so much for the awesome experiments.  We are off to go do more!

  6. David says

    I am doing the experiment for school and I how much alum would I use. Also what is the topic of this project like what are we trying to find out?

    • rachelle says

      Hi David, We didn’t run the experiment with alum or epsom salt (per your question below), but if you do a search on alum/epsom salt + egg +geodes, I bet something will come up. You could run the experiment with different amounts of each substance and compare the results. Good luck!!

    • rachelle says

      Hi Anna,
      I’m sure you’ll love it. It’s such an interesting process and you’ll learn a lot, first hand, about diffusion. Not to mention, the results can be stunning.
      Rachelle

      • anna says

        i used sugar, water(control), and sea salt. The results are quite cool. i hope i get an a on it.

  7. Julie Adams says

    Hi! My daughter was considering doing this as her science fair experiment but we are having a hard time coming up with the actual question. Any suggestions? Thanks!

    • says

      Are Egg Shells permeable? (These could lead to a discussion on Salmonella and if it is on the surface of eggs or also on the inside.)

  8. Margaret-Ann McKee says

    My son and I found this experiment just two days before Easter and are so excited about it. We used kosher salt, sea salt and sugar. So far the kosher salt is doing well I am excited to see how the sugar turns out but those crystals usually take longer. Thanks so much for this fun activity!

  9. MamaLinds says

    Hi, thanks for the really cool idea! You discussed what happens after 5 days, but I wonder what happens if they are left undisturbed for weeks? Do they mold or continue to crystalize? We are planning to use this as a science experiment for my daughter and we are just trying to figure out the timing of it!

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