Lesson Plan

From Core to Crust

side view of mantle and crust

Side view of mantle and crust

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Earth Science, Geology
2-3 hours
Group Size:
Up to 36 (6-12 breakout groups)
National/State Standards:
stratigraphy, earth science, geology


Students act out different parts of the Earth and then build models of the Earth showing its layers. (CLASSROOM ACTIVITY)


  • Students will be able to name the parts of the Earth.
  • Students will understand that the Earth is dynamic.


The Earth, like the life on its surface, is changing all the time. Parts of it are molten and slowly rise, cool, and sink back toward the Earth's core, like soup simmering over a fire. Continents drift around the globe creating the features we think of when we think of geology. But most of the Earth lies unseen between our feet and the other side of the world.

The Earth is made up of the crust, the mantle, and the core. Although geologists have only drilled a few miles into the Earth's crust, they have indirectly deduced much about the remainder of the planet's composition.

Earth layers

The Crust
What we walk on and see is the crust. It is wafer thin, only 3 to 22 miles thick. If the Earth were the size of a billiard ball, the crust would be as thick as a postage stamp stuck to its surface (think how thick the membrane of life would be that coats the Earth!). The crust is broken up into enormous sections the size of continents, called tectonic plates. Earthquakes and volcanoes are common along the margins of these moving plates. The volcanic activity at Craters, however, is not related to it lying on the edge of a continental plate. Rather, geologists theorize that southern Idaho has passed over a hotspot or mantle plume.

The Mantle

The mantle is about 1,800 miles thick and is under pressure and therefore denser and hotter than the crust. The mantle can be subdivided into three regions.
The Lithosphere.
The lithosphere includes the crust and the outermost part of the mantle. It is relatively cool and rigid and float upon the hotter layer below.
The Aesthenosphere.
This zone in the upper mantle is hot enough to flow at a very slow rate of speed and acts as the sea upon which the lithosphere floats.

The Deep Mantle. Beneath the asthenosphere the rock becomes progressively more plastic. Many geologists believe that huge convection currents mix this part of the mantle as it rises toward the asthenosphere, cools, and sinks back toward the core again.

The Core

Because of gravity, the densest materials are found near the Earth's center, mostly iron and nickel. The 2,100 mile thick core is under the pressure of 1,800 miles of mantle and is therefore very hot. Geologists believe this is the main source of heat for the geologic events we know about in the mantle. Based on how energy waves pass through the Earth, geologists know that the core is in two layers.
The Outer Core.
The outer core is molten and responsible for Earth's magnetic field.
The Inner Core.
The inner core is extraordinarily dense, solid metal.

See "Additional Resources" below for links to introductory materials about the geology of Craters of the Moon.

From the Teacher's Guide to Craters of the Moon.


  • Chalkboard
  • Scissors
  • Cardboard milk cartons or other similar boxes
  • Small ziplock bags
  • Masking tape
  • Nontoxic paints or pens
  • Clay or ...
  • Dough (for ingredients see recipe at end)
  • Water
  • Cardboard
  • Glue
  • Construction or butcher paper


Park Connections

Earth's layers are not as distinct as illustrated here and by your models. There are transition zones and variations in densities within layers. The presence of Craters of the Moon not on the margins of continental plates demonstrates that the layers beneath our feet are far from uniform.

Additional Resources

Geology of Craters of the Moon:
For Teachers
For Students


Deep Mantle