Kids are natural scientists. From babyhood, in fact, they are always putting hypotheses to the test. When I throw my spoon on the floor, I think Mommy will pick it up. I’ll test it! Or, When I get too close to the stairs, Daddy will pick me up. I’ll test it! As they grow older, it’s no different. They are always testing and learning.
Channel that scientific curiosity by making your own geodes in a fun kitchen experiment!
What is a geode?
A geode is a round or oval-shaped rock that’s plain on the outside but lined with beautiful crystals on the inside. Ask your child to imagine how such a rock could form. After a few guesses, you can explain that geodes form in rocks that are hollow. When air gets trapped inside a volcanic rock, for example, a bubble can form. Or, a hollow can be left inside rock when the remains of an animal burrow or tree roots decompose. As water moves through the bubble, crystals form and over millions of years, these crystals build upon each other.
You’re going to speed up the process and make your own geode! It will take you and your child less than a week from start to finish and each step of the experiment below takes less than ten minutes. Perfect for your little scientists’ attention span!
And in case you thought it couldn’t get any more exciting than that, let me tell you this: the geode you and your child are going to create will be edible! Oh yes, there’s chocolate involved.
Ready to start? Here’s what you’ll need:
3 cups of sugar
1 cup of water
Food coloring (optional)
1 cup of flour
White chocolate chips
Milk or dark chocolate chips
Sandwich cookies (like Oreo)
1. First, you need to make a supersaturated sugar solution. Mix three cups of sugar and one cup of water in a pan. At room temperature, that quantity of sugar will not dissolve in that quantity of water. But when you bring it to a boil for several minutes, stirring continuously, the sugar will dissolve. That’s your supersaturated solution. You can check if the solution is ready by bringing up a spoonful. If you can still see little bits of sugar floating around in it, it’s not ready. When the liquid is completely clear, you’re ready to go. At this point, you can add food coloring if you want a colored geode.
2. Next, take a medium-sized bowl and fill it halfway with flour. Take a large sheet of aluminum foil and shape it in the bowl, folding the edges of the foil over the edges of the bowl. Give it an irregular shape to make it look more like a rock, but not so many points and crevices that it will be difficult to peel the foil off later. Pour your supersaturated sugar solution into the bowl, cover it with another sheet of foil and let it sit on your counter for a couple days.
3. After two or three days, uncover the bowl and lift the foil out of the bowl. Pour the excess solution into another bowl and then carefully peel the aluminum foil off the rock candy crystals that have formed. Set this hardened candy bowl upside down on a paper towel and let it dry for another day.
4. Melt some white chocolate chips. You can do this in a double boiler on the stove or in the microwave, being careful to stir every fifteen seconds. Set your geode upside down on top of a glass and pour the chocolate over the top, using a spoon to spread it down over the edges. Let the chocolate harden a bit.
5. Next, melt the (milk or dark) chocolate chips. Pour this chocolate over the white chocolate, using a spoon to spread it down over the edges. Put a couple chocolate sandwich cookies into a bag and crush them. Sprinkle the crumbs over the chocolate before it sets to create a rough, rocky look. Let set and that’s it!
Now, you may enjoy your beautiful (and tasty) geode!
We hope you enjoy your edible experiment! We’d love to know what other kid-friendly science experiments you have done with your kids. Share in the comments below.
Looking for more activities to do with the kiddos? See below!