Rice Krispies Earth's Layers

Greetings, Earthlings! Did you know the Earth has four layers? To learn more about the layers, I am suggesting you try this fun project out with your kids!

The four layers of the Earth are the crust, the mantle, the outer core, and the inner core. When you are making these treats, it is important to understand how thick each layer is compared to one another. The crust is not very thick relative to the rest of the earth. For oceanic crust, the average thickness is between 3 and 6 miles. Continental crust is a good deal thicker, with an average thickness of about 22 miles. The distance from the Earth’s surface to its center is about 4,000 miles which means the crust does not even cover 1% of the distance. The mantle is the largest layer within the earth, spanning about 1,800 miles. The outer core is the earth’s second thickest layer at 1,500 miles thick and the inner core is only about 760 miles thick. But, being the earth’s inmost layer, it’s also a full sphere shape.

Take a deeper look into these key terms before jumping into this workshop.

Key Terms

Crust: The earth’s crust is the top and thinnest layer. It’s divided into two types, oceanic and continental. The crust is unique in that it’s the only layer made entirely of moving plates. This motion is actually the basis for a major theory: plate tectonics. The crust is made primarily of three elements: oxygen, silicon and aluminum.

Mantle: The layer right below the crust is the mantle. It is an interesting layer in that it has both solid and liquid parts. By far, most of it is liquid.

Outer Core: The outer core is fluid, like the mantle. The outer core is extremely hot at 8100 degrees Fahrenheit. This causes it to be a liquid.

Inner Core: The inner core is solid and is not unlike the outer core in terms of composition. Heat increases as we go deeper into the earth (the inner core’s temperature is 11,000 degrees Fahrenheit). But, so does pressure. In the earth’s inner core, there’s actually so much pressure that it prevents the rock from melting. It pushes the atoms together, maintaining a solid state.


Food coloring

Rice Krispies






Step 1: Make four separate batches of rice krispy treats, four separate colors (Melt butter and marshmellows together, add food coloring, add Rice Krispies)

Step 2: Spray bowl with Pam so the Rice Krispies won’t stick

Step 3: Cover the inside of the bowl with batch 1

Step 4: Cover batch 1 with batch 2

Step 5-6: Repeat for batch 3 and 4

Step 7: Put in the refridgeatr for about 30 minutes to cool

Step 8: Remove from the bowl and Ta-Da! You have the Earth’s Layers!

Photos of finished products can be found here and here

More on this project can be found here. If you need more directions, look at this site.

More information on the Earth’s layers

Here is my favorite Magic School Bus episode on the Earth’s layers