By Robert Ceville, Updated Mar 24, 2022

Students and judges alike appreciate a visual representation of Earth’s structure. A simple, 6‑inch plastic foam ball can become an engaging model that illustrates the atmosphere, crust, mantle, outer core, and inner core—all within an hour.

Step 1: Prepare the Base

Slice the foam ball in half with a sharp knife. Use one hemisphere for the model; the other can be saved for a future project.

Step 2: Depict the Atmosphere

Outline a blue layer about ¼ inch thick around the outer rim of the hemisphere to represent the atmosphere.

Step 3: Add the Crust

Color a thin, ⅛ inch band inside the atmospheric layer in dark brown, black, or gray to show the Earth's crust.

Step 4: Illustrate the Cores

Mark a 1‑inch circle at the center in bright yellow for the inner core. Surround it with a ¼ inch orange ring to depict the outer core.

Step 5: Represent the Mantle

Fill the remaining interior with brown to symbolize the molten mantle. Optionally, add light markings to hint at land and water distribution.

Step 6: Label Each Layer

Cut five small rectangles from paper, write each layer’s name, and attach them with straight pins to the corresponding sections.

Materials Needed

• 6‑inch plastic foam ball
• Sharp knife
• Colored markers (blue, dark brown/black/gray, bright yellow, orange, brown)
• Pen
• Paper
• Scissors
• 5 straight pins