Seeing Inside the Earth

Shadow zones and the core

An interactive lesson with 6 steps, about 5 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• Seismic waves reveal Earth’s layered interior.
• The S-wave shadow shows the outer core is liquid.
• Inge Lehmann discovered the solid inner core in 1936.

Steps

1. An X-ray of the planet
2. The S-wave shadow
3. Inge Lehmann’s discovery
4. Through the middle
5. The shadow of the core
6. How big is the core?