Incredible Egg Geode
Forgive the wordplay, but we love to do “eggs-periments.” Get it? We’ve made naked eggs, put eggs in a bottle, folded eggs, and we’ve even shown you how to determine whether an egg is hard-boiled or raw. We want to find something new and amazing to do with eggs, and the Incredible Egg Geode is “eggs-actly” what we are looking for.
- Food coloring
- Alum powder (look in the spice section of your local grocers)
- Paper towels
- You have an egg, now you need to get all the yolk and egg white out of it. WAIT! You can't just crack the egg like you're making breakfast. You need that egg in one piece. Use a pushpin to carefully poke a hole in each end of the egg.
- Put your mouth on one end of the egg and blow the yolk out through the other hole. Blow the yolk into a bowl or garbage disposal, depending on whether you're hungry or not.
- Now that you don't have an egg so much as an eggshell, carefully cut the shell in half, down the egg's length, with a pair of scissors. If there are any small pieces around the edges, go ahead and pull them off. They're of no use to you.
- Continuing to exercise caution (who knew science was so fragile?), wipe out the inside of the egg with a paper towel. Get the interior surface of the egg as clean and dry as possible without cracking it.
- Drop a small amount of glue into the egg and use a paintbrush to spread it around. Try to cover the entire interior surface, all the way up to the edges, of the egg with glue. Add more glue if needed.
- Quickly, before the glue dries, cover it with alum powder. How much? Cover it all! Our experiment tester suggested the word “generously”… so use quite a bit.
- So you covered the glue with alum powder, now what? Well, your options are to sit around until everything is completely dry or let it sit overnight. The first option gets really boring and you need your rest, so come back tomorrow and we'll pick the experiment up there.
- Is it tomorrow yet? Yes? Then let's do this!
- Bring two cups of water (that's 473 mL to everyone outside the U.S.) to the point where it is almost boiling. Pour the heated water into a beaker or glass and stir 30-40 drops of food coloring and 3/4 cup of alum powder into the heated water.
- Let the colored alum solution cool for around thirty minutes.
- Once the colored alum solution has cooled, place the egg, opening up, into the solution. Push the egg to the bottom of the beaker with a spoon and allow the egg to sit in the solution for 12-15 hours. That's a long time, right? Good thing you practiced patience by waiting for the glue to dry earlier.
- After the 12-15 hours have passed, check out your egg. It's grown crystals! Carefully remove the egg and place it on a paper towel or drying rack to finish the geode-creation process.
While a geological geode is a mass of minerals within a rock that can take thousands of years to form, your Incredible Egg Geode only takes a couple of days. See? All that waiting could have been much worse.
How Does It Work?
Your egg geode is formed through a process called sedimentation. The heated alum solution contains suspended particles of alum powder and as the solution cools, these particles of alum begin settling. When the alum particles settle towards the bottom of the beaker or glass, they begin crystallizing. With the alum-covered egg at the bottom, the alum particles from the solution begin attaching themselves to the egg. Covering your egg in alum powder beforehand gives the suspended alum particles a surface to which they can more readily attach themselves. The particles that settle onto the surface of the egg crystallize, and you will also see crystallization on the bottom and sides of the beaker or glass.
- Tease! Review by Joahna
Think this looks really fun and my nephew watched the video with me and we were totally committed to doing it! Then we tried to find Alum, figuring we'd need almost a cup per color we wanted to do. The only Alum we could find was a tiny container hidden at the grocery store, about 1/6 of a cup in a package and selling for $3.25 each. They had three of them. Idea abandoned...
(Posted on April 6, 2012)
- egg geode Review by kerrie schulze
I was amazed at how easy this was. The results were better than I expected.
(Posted on April 7, 2012)
- Alum Powder specifics Review by Heather
I've tried this experiment 3 times, the 3rd time was finally the charm. The first time I bought the Alum powder from Kroger, it didn't work. The second time I ordered it offline from nuts.com, that didn't work either. Then I found someone that said you have to make sure you buy the alum powder with potassium in it or the eggs won's grow crystals. This seemed to be the problem, because I bought my 3rd batch from talasonline.com (it specifically says its alum powder has potassium in it) and my eggs grew crystals. Also, for the 2 cups water and the 3/4 cups alum powder, this is for 1 egg (2 halves). Hope this helps for anyone who makes this in the future.
(Posted on November 15, 2012)
- Very cool experiment! Review by Erin
My class is doing this experiment this week. We did a trial experiment today. When we submerged the egg into the water/alum mixture, the eggshell floated up and stayed at the surface. Will this work or are we supposed to leave the spoon in to weigh the shell down?
(Posted on May 15, 2012)
- Amazing Review by Jessica Miles
My son did this experiment for his school science project. The eggs turned out better than we ever expected! Obviously, the more alum used, the more crystals were formed. We used McCormick Alum powder from the grocery store.
(Posted on November 21, 2012)
- very egg-salent Review by chloe
I loved this experiment! it worked great and my parents spent very little money. I hope this works for the rest of you.
p.s. put two eggs in at a time
(Posted on April 9, 2013)
- Is the eggshell necessary Review by Christy
Can someone tell me if the eggshell is a crucial part of the experiment, or if some other material can be used in it's place? I have a daughter who is allergic to eggs, so if there is another material that would allow the geodes to grow on it as well as the eggshell does, I would love to hear about it. Thank you!
(Posted on July 8, 2012)
- Total fail Review by Benjamin
My 8 year old daughter decided to try this for her 3rd grade science fair. She and her mother followed the directions exactly and absolutely nothing. Then I did the experiment with her myself, exactly following the directions. Nothing. She had to miss the science fair.
It appears that most people had the same experience with it not working, or one not even moving forward. Does every review automatically get 5 stars no matter what then, even if they say it was a fail? Would be nice if you listed where to buy the correct alum powder online too, assuming there is incorrect alum powder.
We're sorry that you didn't get the results that you were looking for with the demonstration, but unfortunately, there are too many factors that can change to guarantee results during every attempt. To answer your question regarding the type of alum powder, we used plain, powdered alum (Kroger brand). Hopefully you are able to replicate the results!
- Steve Spangler Science Web Team
(Posted on February 22, 2013)
- flop Review by 5th grade teacher
spent $80 dollars on Alum. tried it with 2 classes for a mothers day gift. 48 eggs. Not a single one turned out. No crystals just a bunch of colored egg shells.
(Posted on May 10, 2012)
- Eggs-cellent Egg-speriment! Review by Karen
This is so much fun, Steve! Thanks for the appropriate timing. I did this with K-5th graders as well as a little more challenging version with 9-12 graders, and we all had a blast. Very easy, great video explanation.
(Posted on April 4, 2012)