How to Create Crystals with Common Kitchen Ingredients

4 min to read
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Whether your student is already on track to win a future Nobel Prize or they whine and groan at the mere mention of science, engaging, at-home science experiments with kitchen ingredients are an excellent way to pique your child’s interest in science. 

When students create crystals with these common ingredients, they mimic the process that occurs in order for geodes to form in nature. 

Before we discuss the five easy steps for creating these colorful crystals, let’s do a quick overview of crystals in science.

Crystals in Science: A Quick Geology Background

What Are Geodes?

Geodes are round rocks with crystals inside. Most geodes are made of quartz crystals, but some contain purple amethyst. Geodes begin as a bubble within a layer of rock. These bubbles can be formed by an animal burrow, tree roots, air trapped within exploding volcanic rock, or any number of other processes.

Where Do Geodes Come From?

Most geodes are found in sedimentary and igneous (volcanic) rocks. Geodes can form in a lot of different ways, like when rock grows around a pocket of gas or a space in the earth that isn’t filled with anything else. Minerals in the groundwater that seeps in and out of these hollow rocks over thousands of years are deposited and grow into crystals.

You can find a lot of geodes in the Midwest, particularly where Illinois, Iowa, and Missouri meet, as well as in the deserts of the Southwest, including in California, Arizona, Utah, and Nevada.

Geode Crystal Identification

From the outside, most geodes look like common rocks, but when they are opened up, the sight can be breathtaking. Geodes have a durable outer wall and a hollow space inside, which is what allows the crystals to form. So, if a rock feels lighter than the surrounding rocks, it may be a geode. To identify a geode, you typically must break it open with a rock hammer or use a rock saw.
For older elementary students, cracking your own geodes can be entertaining, educational, and cathartic all at once. And they’ll have a shimmery souvenir!

Create Your Own Eggshell Geode Crystals from Home

With this bit of background on the geology of crystals, your student is ready to enjoy this exciting at-home science activity. While crystal-filled geodes take thousands of years to develop in nature, you can produce your own crystals in less than a day using eggshells and other common kitchen supplies. Here’s how:

Materials Needed

Making geode crystals at home is super simple and only requires a few  common household items. These include:

  • Hot water
  • 3 eggs
  • Sugar
  • Baking soda
  • Table salt
  • Food coloring (red, blue, and green)
  • Cupcake pan
  • Small glass or paper cups

Step 1:

With the help of an adult, crack each egg as close to the narrow end as possible. Only do this with one side, leaving the other narrow end intact. Carefully clean out the bottom of each egg with hot water and place the shells in the cupcake pan. If you have trouble standing them upright, try supporting them with a tissue.

Step 2:

Use the small cups to create the three mixtures listed below, which will fill each shell. 

Mix 1 Mix 2 Mix 3
1/4 cup water  1/4 cup water 
1/4 cup water 
1/3 cup sugar
1/3 cup baking soda 1/3 cup salt
1 drop red food coloring 1 drop geen food coloring 1 drop blue food coloring

Step 3:

Pour your solution carefully from the cup into the eggshell, making sure it’s as full as possible without letting it overflow or topple over.

Step 4:

Find a safe spot to store your shells. As the water evaporates, crystals will form inside the eggshells.

Step 5:

Compare the shells over the next five days to see which mixture grows the most.

What Happened?

In nature, geodes form when minerals that have been dissolved in water enter hollow spaces and harden into an outer shell. Over time, the geode’s crystals expand toward the center, filling its interior. In this activity, the dissolved mineral that forms inside the eggshell is represented by sugar, salt, and baking soda. 

More Science Experiments at Home

Encourage your student’s interest in science by making other hands-on STEM experiments. Students who enjoyed this activity may also like our make your own fossils and others may prefer getting out of the house and into nature with these educational outdoor activities.

If your student is interested in doing more science fair projects with crystals, try repeating this activity with different materials like brown sugar or Epsom salts. See what else you can discover!

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