Science Buddies: "Ask an Expert"

I am going to be researching geodes for my science project. For my science project, I am going to take an empty egg shell and turn it into a geode. My question will be, "What substance can crystallize an egg the most?" I was going to try using salt, which is why I ask you, "Can salt (sea and kosher) crystallize on an empty egg shell? (mixed with water)

-paige123

I am doing research for my science project, and I was wondering if you could tell me about some biological characteristics about geodes. My research paper is due this Friday.

Hi Paige,

That’s a fascinating idea you have to make a ‘geode’ out of an egg, but I am not so sure this really qualifies as a science project. First off, what is your hypothesis? In science you make a statement about something based on your observations then design experiments to prove or disprove the statement [hypothesis].

As I understand it, a geode forms when a solution of a mineral enters a hollow space inside certain kinds of rock. As the water evaporates, the mineral crystallizes out on the inside. You could make a model of this process using an egg—with the contents removed by making a small hole and blowing out the white and yolk. Then you could stop up one hole with glue and use a syringe to inject a saturated solution of salt or something more colorful like copper sulfate.

The water should evaporate through the egg shell in time leaving a pretty deposit of crystals on the inside that you can see by breaking open the egg shell.

Here’s a Scibuddies project about the effects of temperature on crystal growth using a solution of borax as the source of crystals: https://www.sciencebuddies.org/science- ... ml#summary
You can read the background and methods in that project to learn how to grow crystals, plus there’s a ton of information on Google and YouTube about crystal growing.

Your project is unusual because the crystals will be growing inside an egg and you won’t be able to see them till later when you break open the egg—but that will be the fun part! I would use chemicals like copper sulfate but these can be toxic if not handled properly, so it’s probably best if you simply add food coloring to your solution of table salt, sugar or borax to get pretty crystals. Here’s a good website that has lots of information on crystal growing projects: http://chemistry.about.com/od/crystalsf ... ojects.htm

Please keep all your posts in ONE thread so we can find them easier. Let us know specifically how you want to do your project and we can help you with the details.

Best wishes,

Sybee

Paige. We merged your two questions regarding geodes into this one thread topic. Sybee has given you excellent advice. Good luck with your project!