Earth's Layers

A diagram showing the layers that make up planet Earth and their thicknesses.

NASA; Public Domain

The Earth is like an onion; it has layers! This activity will show you what the inside of the Earth looks like. Look below for step by step instructions with pictures!

You will need:

• 5 colors of play dough (yellow, orange, red, green, blue, and optional white)

• A paper plate

• A plastic knife

• A clear plastic straw (It’s best to have a thick straw so it doesn’t bend)

• Diagram of the Earth’s layers (provided)

 

The play dough colors have been rolled and are ready to start.

Florissant Fossil Beds National Monument

Instructions

Step One:

Roll a small ball (about the size of a gumball) of each color of play dough. The yellow ball can be slightly smaller than the rest.

Step Two:

Take the small ball of yellow play dough and put it in the center of your plate.
This is the first layer called the inner core. Each layer has a unique density (density=mass/volume). The density will decrease with each layer as we move outward from the inner core. This is due to gravity. The denser something is, the more gravity will pull on it. So the densest materials are pulled closer to the very center of the Earth while less dense layers settle further away from the center. The inner core is at the center of the Earth because it is the densest, made of solid iron and nickel.

 

The orange ball has been flattened and is ready to be added to the Earth model.

Florissant Fossil Beds National Monument

Step Three:

Take the ball of orange play dough and flatten it on top of the yellow ball so that the yellow is completely covered. The whole ball should look like it is orange with no yellow showing.
This new layer is the outer core. The outer core is slightly less dense than the inner core.

Step Four:

Flatten the red ball and wrap it around the orange like you did in step three. Make sure there is no orange showing now.
This is the mantle. This layer is made up of molten rock called magma. When the molten rock is erupted onto the surface it is then called lava.

 

The outer core has been added. Make sure the yellow inner core is completely covered.

Florissant Fossil Beds National Monument

Step Five:

Flatten the green ball and cover the red with it.
This is the crust. The Earth's crust is made of solid rock that floats on top of the magma in the mantle like how ice floats in water. The continents are part of the crust.

Step Six:

Flatten the blue ball and wrap it around the green.This color represents the atmosphere, which is made of gasses making it the least dense and outermost layer that makes up the Earth.

 

The play dough model Earth is done! Time to look inside!

Florissant Fossil Beds National Monument

Step Seven (Optional):

If you’d like, you can put some bits green on top of the blue to represent the visible parts of the crust. If you have white you could also put some bits of white as well to represent clouds in the atmosphere.

 

With the play dough model cut in half you can see the layers on the inside.

Florissant Fossil Beds National Monument

Step Eight:

Put your play dough model of Earth on the paper plate. Use the plastic knife to carefully cut the play dough ball in half and look at the inside of it. You should see the different layers of color.

This is what a cross section of the planet Earth would look like. Can you make comparisons between your model of Earth and the diagram?

 

Taking a core sample through the "center of the Earth".

Florissant Fossil Beds National Monument

Step Nine:

Lay one half of the model on the plate with the flat part down. Take the straw and push it through the center. Pull the straw through so you can look at it. There should be play dough stuck inside the straw.

 

This core sample shows what the Earth's layers look like under the surface.

Florissant Fossil Beds National Monument

You are looking at a “core” sample of what the Earth looks like. Geologists will take core samples to look at rocks that they can’t see on the surface.

New Words!

• Density: noun; the mass of a substance per unit volume (Density= mass/volume)

• Gravity: noun; the gravitational attraction of the mass of a heavenly body (such as Earth) for bodies at or near its surface

• Geologist: noun; a person who studies the history of the Earth and its life as recorded in rocks

• Magma: noun; molten rock material within the earth

• Lava: noun; melted rock coming from a volcano

 

Earth Layers Lesson Plan

Lesson Plan for Earth Layers activity