I was the kid who looked forward to the science fair every year. I had a hard time narrowing down what topic I wanted to talk about. I LOVED it. I didn’t let my parents help and I always went above and beyond what was required. One year (4th grade) I did a project on Radios. I built a radio, I went to a radio museum exhibit, read every book in the library (dude, the Internet didn’t exist…) but that apparently was not enough. I wrote a rap. Yep. A RAP song people. About radios. And I performed it for everyone who came by my booth. I wish I were kidding. And I got INTO it. Swaying to the beat. I was a skinny white girl rapping about radios.I would give anything to have a video of that!
My kids have not done science fair projects in school. Are they extinct? Is it just here? Any way, my kids have been dying to do this experiment ever since I found it on Pinterest so we went for it. I LOVE doing this kind of stuff with my kids :) My boys are obsessed with all types of rocks so we made geodes and learned more about them.
For the science project, we used:
The instructions said to use egg shells but I figured that would be way too fragile for my boys. They break ACTUAL rocks….. So we made the “shell” of the soon to be geode out of polymer clay.
Once we were done we baked them for 20 minutes at 275 degrees in the oven. We let them cool before moving onto the next step.
We used a cheap paint brush to apply a thin coat of glue to the inside of the shell. Then we put Alum in them and swished it around until the glue was covered. (Alum can be found with the spices in the grocery store) Shake out any extra back into the bottle. The point of this is so the Alum solution used later will be attracted to the alum crystals to form larger crystals. We left one with out glue and Alum as the control.
Now you make the Alum bath or growing solution. Add 2 cups boiling waster to a glass bowl. Then add food coloring (30 -40 drops). Then add 3/4 cup of Alum (2 bottles) and stir until the Alum has completely dissolved. If there are still Alum crystals you can microwave it.
Let the water cool about 30 minutes and then put the soon -to- be- geodes in the growing solution with the open part of the shell facing up. Put the bowl somewhere where it won’t be disturbed. Let it sit overnight at least. The longer you keep them in there, the more they will grow.
Okay, now we needed a presentation. We headed to the store and found these boards
The boys helped me glue the letters I cut out with the X-TREME glue stick.
I had them decided what they thought would happen to the one that didn’t have the Alum glued to it. They decided that it wouldn’t grow crystals at all.
Once the experiment was complete we were able to finish the board.
Here it is all put together!
And here are the geodes……….
The one without the alum glued on it still form some crystal but not as much as the others. It was fun to talk to the boys about why. I think over all they had a good time for it. I was a bit rushed to finish it so I am glad this wasn’t really for school :)
*This post was compensated as part of a social shopper insight study for Collective Bias.